Backport relevant changes from gitlab-org/gitlab-ee!51

To do:

- [x] Update gitlab-shell

See merge request !1822

[ci skip]

Correctly set comparison first commit when range includes a merge commit

Fixes #3207.

See merge request !1814

See merge request !1705

Add notification to the former assignee upon unassignment

Replaces !1769

Fixes #3395

See merge request !1818

Prevent the last owner of a group from being able to delete themselves
by 'adding' themselves as a master

Replaces !1708.

Fixes #1111.

See merge request !1815

See merge request !1816

[ci skip]

[ci skip]

Don't render note edit forms for visitors

Reverted #9820, github/task_list need a form, textarea for update.

Revert "Merge pull request #9820 from huacnlee/avoid-render-form-in-notes-list"

This reverts commit 63144cd0, reversing
changes made to 8ab5df9d.

Reverts https://github.com/gitlabhq/gitlabhq/pull/9820

See merge request !1804

Fix md syntax in doc/api/commits.md

Ensure variable in mail is evalled

I received this snippet in the mail:

```
Content-Type: text/plain;
 charset=UTF-8
Content-Transfer-Encoding: 7bit

Project #{@old_path_with_namespace} was moved to another location

The project is now located under
```

This MR fixes it.

Notes:

* I did a quick grep on other 'text.erb' files, but this was the only one with this type of error
* I made no changes to the specs. The only [spec](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/spec/mailers/notify_spec.rb#L412) I could find passes because (I assume) the correct value is in the html-part

See merge request !1706

Make ProjectWiki touch Project#last_activity_at after wiki actions

Closes #3026

See merge request !1803

Rewrite HTTP links to force TLS, where possible

I got annoyed at the fact that the links on the profile page don't force the use of TLS, so I grepped through the entire source tree, tested all the links I found, and replaced them if possible.

See merge request !1806

Create milestones in the group

When you work with groups its quite often you want to create same milestone in multiple projects. This MR allows you to do so

For #3488 
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

See merge request !1797

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

8.2.rc1 documentation updates

[ci skip]

See merge request !1798

Closes #3026

This reverts commit 63144cd0, reversing
changes made to 8ab5df9d.

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

Add index uniq

Added unique on oid index. Removed the second index since it is unnecessary. 

See merge request !1810

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

Show specific runners from projects where user is master or owner

This fix for permission escalation when handling specific runners.

The users were allowed to assign runners from projects where they were guests.


See merge request !1809

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

* Group attachments are not supported so I removed attach file link
* Added changelog item
* Add markdown hint to project milestone form
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>