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

This refactors the Markdown pipeline so it supports the rendering of
multiple documents that may belong to different projects. An example of
where this happens is when displaying the event feed of a group. In this
case we retrieve events for all projects in the group. Previously we
would group events per project and render these chunks separately, but
this would result in many SQL queries being executed. By extending the
Markdown pipeline to support this out of the box we can drastically
reduce the number of SQL queries.

To achieve this we introduce a new object to the pipeline:
Banzai::RenderContext. This object simply wraps two other objects: an
optional Project instance, and an optional User instance. On its own
this wouldn't be very helpful, but a RenderContext can also be used to
associate HTML documents with specific Project instances. This work is
done in Banzai::ObjectRenderer and allows us to reuse as many queries
(and results) as possible.

And use .rubocop.yml to exclude paths we don't care,
rather than using the cop itself to exclude.

Added discussion_line_code value to note response and use it to query the right row for the discussion UI

Reduces the number of queries needed to redact notes to which
the user does not have access. Also includes an N+1 query test
as a guard against future issues.

This is a follow-up from https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/14327#note_40976854.

A commit comment shows in the MR, but if the MR is from a fork, it will have a
different project ID to the MR's target project. In that case, add an
note_project_id param so that we can pick the correct project for the note.

add /award slash command; Allow posting of just an emoji in comment

* Changed name of delete_user_service and worker to destroy
* Move and change delete_group_service to Groups::DestroyService
* Rename Notes::DeleteService to Notes::DestroyService