Revert "Store pages in shared/pages/fqdn/fqdn/public or shared/pages/fqdn/subpath/public - makes it simpler to implement CNAMEs in future"

This reverts commit 86a2a78f0d13a678899460638add6b862059433e.

This reverts commit 0d73bd93bab349d84910cf14773633b8a66df466.

Store pages in shared/pages/fqdn/fqdn/public or shared/pages/fqdn/subpath/public - makes it simpler to implement CNAMEs in future

- Fix markdown
- Remove how it works section, maybe add it at a later point

- The pages are created when build artifacts for `pages` job are uploaded
- Pages serve the content under: http://group.pages.domain.com/project
- Pages can be used to serve the group page, special project named as host: group.pages.domain.com
- User can provide own 403 and 404 error pages by creating 403.html and 404.html in group page project
- Pages can be explicitly removed from the project by clicking Remove Pages in Project Settings
- The size of pages is limited by Application Setting: max pages size, which limits the maximum size of unpacked archive (default: 100MB)
- The public/ is extracted from artifacts and content is served as static pages
- Pages asynchronous worker use `dd` to limit the unpacked tar size
- Pages needs to be explicitly enabled and domain needs to be specified in gitlab.yml
- Pages are part of backups
- Pages notify the deployment status using Commit Status API
- Pages use a new sidekiq queue: pages
- Pages use a separate nginx config which needs to be explicitly added

Merge CE to EE and fix tests



See merge request !83

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Add new branch and tag action to tree dropdown

Right now, creating a branch or tag is only possible on the project page dropdown or on the commits page. This merge request both actions to the tree header dropdown. Now all repository web actions are available in this one location, plus the existing ones. It makes the operations a lot more intuitive.

## Existing Tree/Repository dropdown:

![Screen_Shot_2015-12-17_at_2.38.50_PM](/uploads/4d83a4b518093ea85f0859b385abcc7c/Screen_Shot_2015-12-17_at_2.38.50_PM.png)

## New Tree/Repository dropdown:

![Screen_Shot_2015-12-17_at_2.32.28_PM](/uploads/1fc18a511774630c5078a7d5c0fbb5b6/Screen_Shot_2015-12-17_at_2.32.28_PM.png)'

See merge request !2144

Remove duplicate entry in the changelog

/cc @DouweM 

See merge request !2149

Use gitlab-shell 2.6.9

See merge request !2143

Use gitlab-workhorse 0.5.1

Improves relative URL support.

See merge request !2134

Upgrade Poltergeist to 1.8.1.

Close #4131 

See merge request !2126

Fix ci_projects migration by using the value only from latest row [ci skip]

This is needed, because for some projects we have duplicate ci_projects.
This was introduced by lack of DB uniqueness on ci_projects.gitlab_id.

The MR fixes edge case by selecting value from latest.

/cc @yorickpeterse 

Fixes: gitlab-org/gitlab-ce#4123


See merge request !2133