Improve pipeline processing

## What does this MR do?
This works on top of https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/5295 trying to solve some edge cases introduced by that Merge Request. The fix switches to a state machine which is already a part of `Ci::Pipeline` and uses events with conditional transitions to switch between pipeline states.

This is approach is much more bullet proof and much easier to understand than a previous one where we were calling a `reload_status!` which manually updated `status`. Previous approach become confusing and prone to number of errors.

## Why was this MR needed?
This improves changes introduced by https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/5295

## What are the relevant issue numbers?
None, yet.

## Screenshots (if relevant)
Not needed.

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added (not needed since changelog for https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/5295 is already introduced)
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [x] API support added (not needed)
- Tests
  - [x] Added for this feature/bug (most of tests do cover the triggering of Pipeline)
  - [ ] All builds are passing
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !5782

Corrected links/usernames in performance guide

## What does this MR do?

This fixes two broken links in the performance guide and removes the mention of Josh as he no longer works for GitLab.

## Are there points in the code the reviewer needs to double check?

No.

## Why was this MR needed?

The guide contained two broken links, and Josh no longer works for GitLab.

## What are the relevant issue numbers?

None.

## Does this MR meet the acceptance criteria?

- [x] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !5772

Remove unused SpamReport model; this was renamed to SpamLog

See merge request !5778

Resolve "New pipeline auto-completion"

## What does this MR do?

Add auto-completion to new pipeline.

## What are the relevant issue numbers?

Closes #19725 

See merge request !5389

update CHANGELOG

add auto-completion into pipeline

add auto-completion into pipeline

add auto-completion into pipeline

update changelog

modify tests

remove empty lines

add auto-completion into pipeline

update changelog

modify tests

switch text_field_tag into text_field

add test to new field

switch context into describe

Update CHANGELOG

render only commit title

update CHANGELOG

add auto-completion into pipeline

add auto-completion into pipeline

add auto-completion into pipeline

update changelog

modify tests

remove empty lines

add auto-completion into pipeline

update changelog

modify tests

update changelog

Update CHANGELOG

add indetation

add tests to pipeline ref

change file name for tests

change file name for spec tests

remove empty line

rename test it

rename test name

removing unexpected changes

removing unexpected changes2

update changelog

Update gitlab-shell to v3.3.3

Finishing touch for https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/5542

![](https://gitlab.com/gitlab-org/gitlab-shell/uploads/bd0d4864f7bd864d38bfb6798fdd4ea3/image.png)

See merge request !5780

Upgrade Rails to 4.2.7.1 for security fixes.

Upgrades Rails from 4.2.7 to 4.2.7.1 for security fixes.

For more information: http://weblog.rubyonrails.org/2016/8/11/Rails-5-0-0-1-4-2-7-2-and-3-2-22-3-have-been-released/

This should be backported to all currently-supported releases.

See merge request !5781

More information available at: http://weblog.rubyonrails.org/2016/8/11/Rails-5-0-0-1-4-2-7-2-and-3-2-22-3-have-been-released/

Merge request link after pushing

## What does this MR do?
Add API to generate new merge request urls if it is a new branch. The API will be called by gitlab-shell 

## What are the relevant issue numbers?

#18266 

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [x] API support added
- Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !5542

Use Ruby 2.3.1

## What does this MR do?

This WIP MR will eventually introduce 2.3 as default language for GitLab CE/EE

## Why was this MR needed?

@connorshea wants to be prepared for Rails 5.0, so we need Ruby > 2.2, so why not go 2.3 already?

## What are the relevant issue numbers?

Closes #12507 

## TODO

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [x] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [x] All builds are passing
- [ ] [Omnibus uses 2.3.1](https://gitlab.com/gitlab-org/omnibus-gitlab/merge_requests/847)

See merge request !4948

Remove need for schedules

Solves https://gitlab.com/gitlab-org/gitlab-ce/issues/15156

\cc @pmachle ,  \cc @dusek

See merge request !3685

Ruby 2.1.8 is used only on master for now, as this would give
confidance in case this commit has to be reverted.

Show member roles to all users on members page

Closes #20614 and https://gitlab.com/gitlab-org/gitlab-ee/issues/850

See merge request !5776

DRY code + fix rubocop

Add more test cases

Append to changelog

DRY changes list

find_url service for merge_requests

use GET for getting merge request links

remove files

rename to get_url_service

reduce loop

add test case for cross project

refactor tiny thing

update changelog

Rename `markdown_preview` routes to `preview_markdown`

_Originally opened at !3700 by @cbartz._

Closes #15000.

See merge request !5774

Remove Grack::Auth: part 2 (LFS)

Deprecate Grack::Auth and handle LFS in Rails controllers under the Project namespace.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/14501

See merge request !5369

Refactor pipeline creation service

## What does this MR do?
This refactors GitLab CI build processing: all builds for pipeline are pre-created when a pipeline object is created. 
The builds are created with a new introduced status `created`.
The builds are then automatically promoted to `pending` when a previous stage do succeed.
This significantly simplifies pipeline processing code solving a lot of problems of lazily initialisation of previous approach (builds were created on-demand).

## Why was this MR needed?
The previous mechanism had a lot of flows (shown in related issues) in how it work, but also in code design. Removing cross model-service-library dependencies.

The current approach moves a build creation to single place `CreatePipelineService` and removes a dynamic dependency on `config_processor` significantly simplifying a build creation and pipeline processing. Pipeline processing is implemented in `ProcessPipelineService`.

This also allows to easily extend GitLab with Manual Actions which is part of 8.10 direction issue.

## Migration problem
~~This MR removes the a on-demand creation of builds in pipelines.
 Pipelines that are running and are in mid-stage (some stages started, but not all) will not be fully evaluated after application restart. 
This happens, because the code responsible for on-demand creation is removed. 
There's no easy way to migrate existing pipelines, other than doing offline migration and putting pipeline processing in migration code (which seems to be a really bad idea).~~

To support old pipelines I added a lazy initialization of builds if none is found.

## What are the relevant issue numbers?
Fixes: https://gitlab.com/gitlab-org/gitlab-ce/issues/12839
Solves: https://gitlab.com/gitlab-org/gitlab-ce/issues/18644 https://gitlab.com/gitlab-org/gitlab-ci-multi-runner/issues/289
Allows to easily implement: https://gitlab.com/gitlab-org/gitlab-ce/issues/17010

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [x] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [x] API support added
- Tests
  - [x] Added for this feature/bug
  - [ ] All builds are passing
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)


See merge request !5295

This change simplifies a Pipeline processing by introducing a special new status: created.
This status is used for all builds that are created for a pipeline.
We are then processing next stages and queueing some of the builds (created -> pending) or skipping them (created -> skipped).
This makes it possible to simplify and solve a few ordering problems with how previously builds were scheduled.
This also allows us to visualise a full pipeline (with created builds).

This also removes an after_touch used for updating a pipeline state parameters.
Right now in various places we explicitly call a reload_status! on pipeline to force it to be updated and saved.

Fix front-end for branches that happen to contain urlencoding escape characters (e.g. %)

_Originally opened at !3574 by @ewiltshi._

- - -

Adding a branch with a name like "foo%20bar" (via command-line) and setting it to the project's default branch causes the project "show" page to 404 for that project. "assign_ref_vars" unescapes the branch name ("foo%20bar" ==> "foo bar"), making GitLab look for a non-existent branch.
This MR adds logic to skip the URL unescaping step in "assign_ref_vars".

Fixes #10772, #14992, #15304.

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- Tests
  - [x] Added for this feature/bug
  - [ ] All builds are passing
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !5770