Moved to OPT_OUT in 7d14b725, Now, by
removing the feature gates, this is an mandatory feature.

Related issues:
- https://gitlab.com/gitlab-org/gitaly/issues/526
- https://gitlab.com/gitlab-org/gitaly/issues/1194

Closes https://gitlab.com/gitlab-org/gitaly/issues/749
Closes https://gitlab.com/gitlab-org/gitaly/issues/1212
Closes https://gitlab.com/gitlab-org/gitaly/issues/1195

When `Errno::EBUSY` is raised during restore, this could indicate that
the directory being restored into is a mountpoint. In this case we
explain the user how to retry the restore.

Instead of renaming existing storage directories to a timestamped
format, create a timestamped directory in a temporary location and move
the individual files and folders inside storage directories to it. This
helps us with nested storage directories.

This reverts commit 54a575f1, reversing
changes made to c63af942.

Move uploads to object storage

Closes #4163

See merge request gitlab-org/gitlab-ee!3867

Can migrate LFS objects to S3 style object storage

Closes #2841

See merge request !2760