refactor login as to be impersonation with better login/logout
Modifies the existing "login as" feature to be called impersonation.
This also adds:
* Application keep track of who is impersonating the user so they can revert back to the original user without having to log out.
* Stores the user profile via `HTTP_REFERER` so you get redirected back to the person you have impersonated once you stop.
## Screenshots:
See merge request !1702
Expose builds feature
Expose builds feature in project settings (as feature).
Enable it by default for a new projects.
I deliberately named it builds instead of CI, because we actualy allow to run tests using infrastructure built-in GitLab. I'm free to change it.
If we are ok, I'll add feature tests for it.
/cc @sytses @dzaporozhets
See merge request !1767
Refactor complex methods
Make flog part of CI check which is not allowed to fail. I used high score (70) and refactored most complex method. In future releases we should lower acceptable score to something like 40..50
Part of #3444
See merge request !1794
Fix "Other Builds" links in Projects Build page
Found a minor issue where all links in the "Other Builds" section of Project Builds was linking to the same build #. This should fix it.
See merge request !1785
ApplicationSetting.current was called in every pages, cache it and expires it after it updated.
This changes will avoid a SQL query in every pages (~0.3 - 0.5ms).
```SQL
SELECT "application_settings".* FROM "application_settings" ORDER BY "application_settings"."id" DESC LIMIT 1
```
These scopes can just sort by the "id" column in descending order to
achieve the same result. An added benefit is being able to perform a
backwards index scan (depending on the rest of the final query) instead
of having to actually sort data.
Implement Build Artifacts
This implements #3028
1. It stores artifacts in shared/artifacts,
1. It adds `artifacts` to `.gitlab-ci.yml`,
1. We use GitLab Workhorse to offload artifacts uploading,
1. To download artifacts it uses GitLab Workhorse X-Sendfile extension,
1. There's one "artifact" per-build. The new upload removes previous one and creates a new one,
1. Default max artifact size is set to 100MB - this can be changed in settings.
Missing things:
1. Support for `.gitlab-ci.yml`: `artifacts: true or git-ls-files` which will upload all non tracked files,
1. Artifacts passing between builds.
GitLab Workhorse changes: https://gitlab.com/gitlab-org/gitlab-workhorse/merge_requests/5
GitLab Runner changes: https://gitlab.com/gitlab-org/gitlab-ci-multi-runner/merge_requests/46
Syntax:
```
artifacts:
untracked: true # default: false
paths: # default: empty
- bin/files
```
See merge request !1584
Display target branch on MR list when it is different from project's default
Fixes#3072
The screenshot below shows both previous and current UI state:
First merge request has default branch as a target, second one has non default branch as target.
See merge request !1741
Dmitriy Zaporozhets
Marin Jankovski
Robert Speicher
Kamil Trzciński
Minsik Yoonand윤민식
Jason Lee
Yorick Peterse
Dmitriy Zaporozhets
Andy Brandt
Drew Blessing
Stan Hu
