Expand Git instrumentation

This instruments some extra `Gitlab::Git` code as well as a collection of `Rugged` constants.

See merge request !2664

Allow manual resize of js-autosize textareas

First, the autosize library was being too controlling and removed the
`resize` property from any elements to which it was attached, removing
the drag handle. We've disabled this behavior in the vendored library
and added a spec to prevent a regression during an upgrade.

Second, we detect (as best we can) when the user manually resizes an
autosize textarea, and then remove the autosize behavior from it and
increase its max-height.

This should allow for the best of both worlds.

Closes #12832

See merge request !2653

First, the autosize library was being too controlling and removed the
`resize` property from any elements to which it was attached, removing
the drag handle.

Second, we detect when the user manually resizes an autosize textarea,
and then remove the autosize behavior from it and increase its
max-height.

This should allow for the best of both worlds.

Closes #12832

[ci skip]

Optimize fetching issues closed by a merge request

Related issue: #12419

See merge request !2625

Render sanitized SVG images

Originally opened at !637 by @stanhu.

Closes https://github.com/gitlabhq/gitlabhq/issues/9265

![Screen_Shot_2016-02-01_at_17.04.01](/uploads/8e5de906698493e127dcdc475da9aaef/Screen_Shot_2016-02-01_at_17.04.01.png)


See merge request !2667

Closes https://github.com/gitlabhq/gitlabhq/issues/9265

Link to Thoughtbot review guidelines.



See merge request !2658

Instead of running ClosingIssueExtractor for every commit in a merge
request we can gather all the commit messages (and the merge request
description), concatenate all this together and then run
ClosingIssueExtractor only once.

The result of this is that MergeRequest#closes_issues is now between
3.5x and 4x faster than the old setup. Using a merge request with 10
commits (each referencing a number of issues to close) this reduced the
call duration from around 200 milliseconds to around 50 milliseconds.

As a result of these changes the Jira related tests for
MergeRequest#closes_issues have been removed. These tests stubbed
Commit#closes_issues meaning that the only code that was really tested
was the call to Array#uniq to filter out duplicate issues. As this code
is no longer used (nor present) the corresponding tests were removed.

Related: gitlab-org/gitlab-ce#12419

Make "Two-factor" casing consistent throughout the application

See merge request !2662

[ci skip]

Improve GitLab flow documentation regarding the WIP merge requests



See merge request !2647

Mark inline difference between old and new paths when a file is renamed

See merge request !2652

Increase the minimum length for commit SHA matching to 7

This is the git default and will help to prevent false positive matches.

Closes #12706

See merge request !2655

Cache BroadcastMessage.current. Fixes #12770



See merge request !2633

Warn admin of granting admin rights during OAuth

Fixes #3951

Warning style the same as the warning a user sees on a archived project.



![Screenshot_from_2016-01-25_20-06-33](/uploads/42e6a218b963311fd20c0b7c87c8cf4f/Screenshot_from_2016-01-25_20-06-33.png)


See merge request !2601

This is the git default and will help to prevent false positive matches.

Closes #12706

Fixed typo for PRIVATE-TOKEN header

Was PRIVATE_TOKEN but should be PRIVATE-TOKEN.
Underscore vs. kebab-case.

See merge request !2624

add missing `RAILS_ENV=production` bit to bundle command

[ci skip]

See merge request !2626

Fix "old version" warning when viewing wiki page's latest version via version_id in URL

Fixes #12712

See merge request !2627