In #37955,we see that the profile had a number of N+1 queries from repeated
access to `cross_reference_not_visible_for?`. This was optimized in previous
versions of GitLab by rendering all notes at once, counting the number of
visible references, and then using that number to check whether a system note
should be fully redacted.

There was also another N+1 query calling `ProjectTeam#member?`, which did not
take advantage of an optimization in prepare_notes_for_rendering that would
preload the maximum access level per project.

Closes #37955

* Improve the descriptive text
* Rename "from" to "Target" and "to" to "Source"
* Swap "Target" and "Source" to have the same order as in MRs
* Reworded "Switch base of comparison" to "Swap versions"
Signed-off-by: NRémy Coutable <remy@rymai.me>

This makes it easier to reuse in EE.

Open the settings section based on the location hash

this will remove the need make N queries (per-note) at the
cost of having to mark notes with an attribute

this opens up the possibility for other special roles for notes

This changes the issue and MR index pages so the pagination system
re-uses the output of the COUNT(*) query used to calculate the number of
rows per state (opened, closed, etc). This removes the need for an
additional COUNT(*) on both pages.

Fix https://gitlab.com/gitlab-org/gitlab-ce/issues/34261

In this instance its subgroups, and given we can't deploy it, we
shouldn't allow it to be shown.

Fixes gitlab-org/gitlab-ce#34864

Its usage has been removed at 2fa22a07.

In Ruby 2.4, Hash#compact exists and returns a Hash, while in
Ruby 2.3,
Hash#compact is implemented by Rails and returns a new
`ActionController::Parameters` instance in this case.

Also, `ActionController::Parameters#compact` is deprecated in
Rails 5.1 so we're using `reject { |_, value| value.nil? }` instead.
Signed-off-by: NRémy Coutable <remy@rymai.me>