proxy_request_buffering should be disabled for gitlab project imports in the default nginx configuration

Summary

request_buffering_off_path_regex should match gitlab project imports by default

Proposal

By default, when importing a Gitlab project, nginx buffers the incoming request before proxying it to gitlab-workhorse. For those situations, omnibus provides a way to override the regex used to match URIs for which request buffering should be disabled (at this time, job artifact uploads, git-receive-pack and git-lfs uploads are matched).

I believe gitlab project imports should also be included in the default regex for which request buffering is disabled by default as they can be large files and it is wasteful for nginx to buffer them entirely before sending them to gitlab-workhorse

References

See #4010 (closed)