Grapify the projects API

Related to #22928 

See merge request !7456

Do not raise error in AutocompleteController#users when not authorized

Closes #25031

See merge request !7817

Speed up Group security access specs

This is the Group equivalent of 13ad9a74

See https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/7779

Part of https://gitlab.com/gitlab-org/gitlab-ce/issues/24899

See merge request !7813

Create pipeline along with builds in the transation

## What does this MR do?

This MR makes it possible to create pipeline along with all associated builds in the transaction, to avoid having empty pipelines when asynchronous job gets terminated.

This will simplify implementation of `PipelineUnlockWorker` in https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/6988 and improve reliability of the CI as a whole.

## What are the relevant issue numbers?

Related to #24361

See merge request !7742

Rename `MergeRequest#pipeline` to `head_pipeline`

## What does this MR do?

This MR renames `MergeRequest#pipeline` to `MergeRequest#head_pipeline`

## Does this MR meet the acceptance criteria?

- [x] All builds are passing

## What are the relevant issue numbers?

Closes #24810

See merge request !7783

Rewrite an HTTP link to use HTTPS

See merge request !7834

fix for builds with no start date throwing an error in cycle analytics events

Instead of the error, we should inform that there is no start date

- [x] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) added
- Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [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 it does - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/24925

See merge request !7738

Fix a transient spec failure

Closes #24772 

See merge request !7825

This is the Group equivalent of 13ad9a74

Add StackProf to the Gemfile, along with a utility to get a profile for a spec

The test suite needs speeding up significantly. This is one tool for investigating it.

Related to #23034

See merge request !7784

Update Sidekiq-cron to fix compatibility issues with Sidekiq 4.2.1

The "Enqueue Now" button would not work in the admin panel due to changes in the Web extension interface: https://github.com/ondrejbartas/sidekiq-cron/commit/88ada926132d4658e3fd370c9f44899b6c88ccaf

Closes #24376

See merge request !7815

https://gitlab.com/gitlab-org/gitlab-ce/issues/25031

Add `null: true` to timestamps in migrations that does not define it

This is to ensure that migrations will still be consitent when we will
upgrade to Rails 5 which default to `null: false` for timestamps
columns.

Fixes #23666.

See merge request !7791

Alert user when logged in user email is not the same as the invitation

## What does this MR do?

Add a note to the invitation page when the logged in user email is not the same as the invitation.

## Why was this MR needed?

Help users to not accept invitations logged in with a wrong account.

## Screenshots (if relevant)

![1](/uploads/78ac6d3db67c9ed60cf74a20ad240d0b/1.png)

## Relevant issues

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/24955

See merge request !7803

CE-specific changes for gitlab-org/gitlab-ee#1137

## What does this MR do?

- gitlab-org/gitlab-ee#1137 is a `technical debt` issue to clean up the EE protected branch access levels (for users and groups) implementation.
- Some of this cleanup bleeds over to code shared by CE and EE, which is why this MR is required.
- An EE-specific MR has also been created: gitlab-org/gitlab-ee!927

See merge request !7821

Fix the width of project avatars in order to adjust alignment within their container element

## What does this MR do?
Adjusts the width of project avatars in order to fix their alignment within the container elements.

## Are there points in the code the reviewer needs to double check?
To make sure there are no unintentional styles changes on unrelated elements.

## Why was this MR needed?
To fix the issue seen below.

## Screenshots (if relevant)
Before: ![Screen_Shot_2016-11-26_at_3.55.58_PM](/uploads/c0012ee7bb5f9e83af41190f71f030fa/Screen_Shot_2016-11-26_at_3.55.58_PM.png)

After: ![Screen_Shot_2016-11-26_at_3.56.17_PM](/uploads/c1236216382e6baa094570c17565e8cf/Screen_Shot_2016-11-26_at_3.56.17_PM.png)

Affected pages: ![Screen_Shot_2016-11-26_at_4.12.38_PM](/uploads/8db6d86a5998843e7b7a755fb4000add/Screen_Shot_2016-11-26_at_4.12.38_PM.png)

## What are the relevant issue numbers?
Closes #24999

See merge request !7772

Changes project dashboard tabs to sentence casing

Changes the nav tab titles on the project dashboard page (```https://gitlab.com/dashboard/projects```) from title casing to sentence casing.

Before: ![Screen_Shot_2016-11-26_at_11.17.23_PM](/uploads/a31c951cf83f7670acee778db9337be5/Screen_Shot_2016-11-26_at_11.17.23_PM.png)

After: ![Screen_Shot_2016-11-26_at_11.17.39_PM](/uploads/a0cb5f6b6771e6f5149750ea1e7beb02/Screen_Shot_2016-11-26_at_11.17.39_PM.png)

Closes #25002

See merge request !7774