The status is shown for
- The author of a commit when viewing a commit
- Notes on a commit (regular/diff)
- The user that triggered a pipeline when viewing a pipeline
- The author of a merge request when viewing a merge request
- The author of notes on a merge request (regular/diff)
- The author of an issue when viewing an issue
- The author of notes on an issue
- The author of a snippet when viewing a snippet
- The author of notes on a snippet
- A user's profile page
- The list of members of a group/user

Whenever we already deal with a User object, let's use the more specific
method avatar_icon_for_user.

Add CHANGELOG entry

Instead of the JS being in charge of the HTML, the HAML now handles it.
The HAML can then check the cookie & show it needed. It also allows the
HAML access to the paths so we don't have to pass that through.

Closes #29955

Closes #28842

Adds rel="noopener noreferrer" to all links with target="_blank"

See merge request !2071

Now it appends a template instead of relying in a partial
to show it.

Also changed the cookie sets to true and false values to make
it consistent with the rest of the javascript.

Fixed some haml and a missing new line

Also improved accesibility and change the id from user_callouts to a class

Also changed the user_callout haml to a partial and
added the corresponding SVG icon