Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

- Offloads uploading to GitLab Workhorse
- Use /authorize request for fast uploading
- Added backup recipes for artifacts
- Support download acceleration using X-Sendfile

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

This column is queried when creating a new project, without an index
this query would lead to a sequence scan.

Fixes performance regression introduced by MR1649

[ci skip]

This adds indexes for the following columns:

* notes.line_code
* ci_projects.gitlab_id
* ci_projects.shared_runners_enabled
* ci_builds.type
* ci_builds.status

Fixes #3086

By using a JOIN we can remove the need for using 2 separate queries to
find a project by its namespace. Combined with an index (only needed for
PostgreSQL) this reduces the query time from ~245 ms (~520 ms for the
first call) down to roughly 10 ms (~15 ms for the first call).