We can now share project so that we don't have to load project twice.
Also, this extracts non-relevant logic out of Deployment.

Update DeploymentsController accordingly

Currently, we do not cap amount of tests returned to frontend,
thus in some extreme cases we can see a MBs of data stored in Redis.

This adds an upper limit of 100 tests per-suite.

We will continue showing the total counters correctly,
but we will limit amount of tests that will be presented.

Extract MR's widget into a separate request

Closes #62723

See merge request gitlab-org/gitlab-ce!29979

This commits extracts /merge_requests/1.json?serializer=widget
Into a separate /merge_requests/1/widget.json endpoint
This will allow to use caching for this request

Refactor code to allow multiple issue boards management for projects
in CE

The merge request widget has a section that includes which issues may be
closed or mentioned based on the merge request description. The problem
is that rendering and redacting Markdown can be expensive, especially
since the browser polls for the data every 10 seconds.

Since these links don't change much and are just nice to have, we only
load them on first page load. The frontend will use the existing data if
the data doesn't appear on subsequent requests.

This saves about 30% of the rendering time of this endpoint, which adds
up to significant savings considering that
`MergeRequestsController#show.json` is called over a million times a day
on GitLab.com.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/63546

This reverts merge request !26853

Use serialization for project boards

See merge request gitlab-org/gitlab-ce!29263

With this commit, we add docs link for confidential
and locked issues to note compose and edit forms

- Add serializers and Grape::Entity
- Replace to_json
- Add specs