Support SendURL for performing indirect download of artifacts if clients does…

See merge request gitlab-org/gitlab-ee!4401

Replaces all the explicit include metadata syntax in the specs (tag:
true) into the implicit one (:tag).
Added a cop to prevent future errors and handle autocorrection.

When calling pre-receive, post-receive, and update hooks, add the GitLab
username as the GL_USERNAME environment variable.

This patch only handles cases where pushes are over http, or via
the web interface.  Later, we will address the ssh case.

Closes gitaly#562

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

Remove superfluous lib: true, type: redis, service: true, models: true, services: true, no_db: true, api: true

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

This revealed an error in our configuration generation in
gitlab:gitaly:install rake task. The fix is included

It seems that bad things happen when two gRPC stubs share one gRPC
channel so let's stop doing that. The downside of this is that we
create more gRPC connections; one per stub.

Use the EnforcedStyleForMultiline: no_comma option.

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

See https://gitlab.com/gitlab-org/gitaly/issues/172

Closes gitaly#168