Drop legacy artifacts usage as there are no leftovers

See merge request gitlab-org/gitlab-ce!24294

We're moving from using terminology related to terminals when
we refer to Websockets connections in Workhorse.
It's more appropiate a concept like channel.

Add support for defining a reactive_cache_worker_finder function
that will be used by the reactive_caching_worker to generate/initialize
the calling object. This allows reactive caching to work with Services
where the object cannot be obtained from DB but a new object can be
initialized.

- Add controls for sorting by title and date
- Execute Gitaly call which now accepts sorting params for wikis

Chnage method used in model to make it
more efficient database-wise
Add additional spec

- added suggestions to mock data
- fixed props to be not required

Legacy artifacts have been correctly migrated to new place -
ci_job_artifacts. Now it's time to remove the related code, but before
that we should ensure it doesn't break anything by using feature flag.

Support time window parameters in additional metrics endpoint

See merge request gitlab-org/gitlab-ce!26228

Do not show system notes on commits in the MR page

Closes #55268

See merge request gitlab-org/gitlab-ce!26396

Adds support for start and end parameters in the #additional_metrics
endpoint of the EnvironmentsController. start and end are meant to be
unix timestamps, per the Prometheus API (as the consumer of this
endpoint will eventually be transitioned to a prometheus endpoint).
This functionality is behind the :metrics_time_window feature flag
for development.