Adds a rubocop rule (with autocorrect) to ensure line break after guard clauses.

Use Commit#notes and Note.for_commit_id when possible to make sure we use all the indexes available to us

Having a distinct class just for that was a bit overkill

Rename classes to (hopefully) clearer names while we're doing that.

Fix the /projects/:id/repository/commits endpoint to handle dots in the ref name when the project full path contains a `/`

Signed-off-by: Rémy Coutable <remy@rymai.me>

Repository#commits is expensive because it has to use Rugged to walk the Git
tree as opposed to doing a direct ref lookup.

Improves performance in #34533

Signed-off-by: Rémy Coutable <remy@rymai.me>

Signed-off-by: Rémy Coutable <remy@rymai.me>

Jordan Ryan Reuter authored 8 years ago and Oswaldo Ferreir committed 7 years ago

`Kaminari.paginate_array` takes some options, most relevant of which is
a `total_count` parameter. Using the `commit_count` for `total_count`
lets us correctly treat the return of `Repository#commits` as a subset
of all the commits we may wish to list.

Addition of a new `Repository#commit_count_for_ref` method was
necessarry to allow the user to start from an arbitrary ref.

Ref #1381

Signed-off-by: Rémy Coutable <remy@rymai.me>