Backport JIRA service

Fixes #3839 

Move EE JIRA functionality back to CE.

- [x] Make it function in manual testing
- [x] Migrate JIRA-specific tests
- [x] Tests pass
- [x] Migrate documentation
- [x] Rollback to previous CE JIRA integration locally, activate on a project then try to migrate db and see if integration still works.
- [x] Final EE search for JIRA references

See merge request !2146

Remove CI_BUILD_BEFORE_SHA from CI documentation

As pointed in #3210, the environment variable isn't usable any more.

See merge request !2118

Clarify Windows shell executor artifact upload support

@ayufan noted that the runner does not support artifact upload for Windows shell executor. This adds a note so users aren't confused.

See merge request !2142

Don't create CI status for refs that doesn't have .gitlab-ci.yml, even if the builds are enabled

Fixes #3827 
Fixes #4157

/cc @grzesiek @dblessing 

See merge request !2139

Do not display project group/name when issue and MR are in same project

I noticed that things seem a bit cluttered for related merge requests
when displaying the group/project name for every item, even when it's
in the same project.

For merge requests that are in the same project as the issue we probably
don't need to display the 'in group / name' bit.

See merge request !2141

Bump Rack Attack to v4.3.1 for security fix

https://github.com/kickstarter/rack-attack/releases/tag/v4.3.1

See merge request !2153

https://github.com/kickstarter/rack-attack/releases/tag/v4.3.1

Remove extra spaces after branchname

See merge request !2152

Fix merge-request-reopen button title

Closes #4069

See merge request !2147

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

Closes #4069

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

Revert sidebar position for issue and merge request
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

cc @creamzy @skyruler 

See merge request !2132

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.

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

Fix ux issue with "This issue will be closed automatically" message

1. Make a nice box for "issue will be closed automatically" message
2. move it below emoji navbar. Otherwise looks wierd. 

Fixes #4134 

# Before
![Screenshot_2015-12-17_00.01.03](/uploads/2a24de77f76ce8a8b61ebabd3a02c83a/Screenshot_2015-12-17_00.01.03.png)

# After

![Screenshot_2015-12-17_00.03.08](/uploads/ccd21b87b7509e79773fabd179bef4aa/Screenshot_2015-12-17_00.03.08.png)
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

See merge request !2129

Add info on using private Docker registries in CI



See merge request !2130

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

Api support for requesting starred projects for user

Closes #4112

Note: probably targets the wrong release in the `CHANGELOG`, though 8.4 was not there yet

See merge request !2127

Move MR Builds tab next to Commits

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/4132

@dzaporozhets We've got two people who feel strongly about this now, @sytses filed an issue for it :)

![Screen_Shot_2015-12-16_at_22.19.35](/uploads/37e705610ba54e386928d7972398c247/Screen_Shot_2015-12-16_at_22.19.35.png)


See merge request !2128

Fix updating and disabling merge button when Merge Immediately is clicked

Fixes #4128

See merge request !2124

Fix Rubocop complain.

See merge request !2125

Fixes #4112