If the project is in a group, the `group.refresh_members_authorized_projects`
is made non-blocking, and we call `current_user.refresh_authorized_projects`
directly.

Projects in a personal namespace are more difficult. Rather than passing the
`blocking:` parameter through the entire `add_master` chain, have the
`AuthorizedProjectsWorker` automatically inline authorizations for three IDs or
less. Since the maximum number of IDs in this path is 2, that has the same effect.

Closes #35994

Every project page displays a navigation menu that in turn displays the
number of open issues and merge requests. This means that for every
project page we run two COUNT(*) queries, each taking up roughly 30
milliseconds on GitLab.com. By caching these numbers and refreshing them
whenever necessary we can reduce loading times of all these pages by up
to roughly 60 milliseconds.

The number of open issues does not include confidential issues. This is
a trade-off to keep the code simple and to ensure refreshing the data
only needs 2 COUNT(*) queries instead of 3. A downside is that if a
project only has 5 confidential issues the counter will be set to 0.

Because we now have 3 similar counting service classes the code
previously used in Projects::ForksCountService has mostly been moved to
Projects::CountService, which in turn is reused by the various service
classes.

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/36622

It was missing and expected it wouldn't hurt anyone

This changes the style of push events that remove tags or branches so
they don't display the commit details. This prevents displaying commit
details such as:

    000000 . --broken encoding

Instead we now simply display the header such as:

    Administrator deleted branch example-branch

This is displayed in the same style as events for newly created
branches/tags.

This commit also ensures that if no commit message is present we simply
don't display anything, instead of "--broken encoding".

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/36685
Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/36722

Fire asynchronous hooks instead.

Using `extend` dynamically can lead to bad performance as it
invalidates the method's cache.

factor out #suitable_notification_level? and check manually by
notification level. this makes the notification logic clear and actually
reflect what is in the documentation as to what should happen with each
setting.

This changes the caching mechanism so we cache both current _and_ future
broadcast messages, then manually filter out those we don't want to
display. This ensures we don't need any additional queries while still
being able to display the right messages at the right time.

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/36661

Backports EE mirror stuck handling feature (https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/2628) to CE