Minor fix in flow 'Merge when build succeeds'

When a user, which is not the merge user, want to removes the source branch
after the automatic merge this might fail because of checks in the
DeleteBranchService

/cc @DouweM 

See merge request !2070

Ci Project migrate

- This doesn't migrate: allow_git_fetch, coverage_regex, timeout. Since this are project configuration settings I would propose to migrate them to `.gitlab-ci.yml`.
- This requires offline migrations.
- It simplifies database models making all CI objects to be attached to: Project.
- It removes Ci::Project, but makes /ci/projects working by adding method: Project.find_by_ci_id for backward compatibility (badges, triggers).
- We should add default `timeout` to Application Settings.
- It misses specs.
- It is based on ci-services-migrate for now.
- It removes CI events.
- It removes administrator CI projects overview.
- It removes CI application settings.

In 8.4 or 8.5 we can remove redundant tables and columns.


See merge request !1987

Ci Services migrate



See merge request !1985

Rename mention of gitlab-git-http-server to gitlab-workhorse

[ci skip]

Closes https://github.com/gitlabhq/gitlabhq/issues/9904

See merge request !2092

[ci skip]

Closes https://github.com/gitlabhq/gitlabhq/issues/9904

Fix wording on "runners" page

An attempt to be a bit more specific and clear on the "runners" page.

[ci skip]

See merge request !2066

Bump Redis requirement to 2.8 for Sidekiq 4

GitLab Omnibus already uses Redis 2.8. There is also a plan to upgrade to Sidekiq 4, which needs Redis 2.8.

Closes #3649

See merge request !1888

Closes #3649

[ci skip]

add details on how to change saml button label

Instructions on how to customize SAML login button text.

See merge request !2079

Make sure notify email always has author info.

Clarify cache behavior

After chatting with @ayufan about CI caching, I added some info to the documentation. This should make it clear how caching currently works.

cc/ @ayufan Is this accurate?

See merge request !2072

Implement new sidebar for issue and merge request pages

This is first step in implementing #3981. We don't have new dropdowns yet so I used some workarounds. 
Also I did it from linux machine without having access to design materials. So some colors/paddings might not match - but I will improve it with next iteration. 

cc @creamzy @JobV 

See merge request !2058

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

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

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

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

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

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

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

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

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

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

Fix typo

[ci skip]

See merge request !2035

[ci skip]

Display referenced merge request statuses in the issue description

See gitlab-org/gitlab-ce#3180 for original issue.
Previously discussed in !1941 and in !1771 before that.

* [x] Show a "Related Merge Requests" list on the issue page under the Description as given by the UI mockup
* [x] Display `all_references.merge_requests` and `note.all_references.merge_requests` 
* [x] Consider displaying the merge request status in addition to the CI status to enable complete merge request status understanding.

See merge request !1991

Revert removal of RedCloth

Revert !2037.

See merge request !2071

Fix delete notes on merge request diff

Fixes #3971

See merge request !2061