Similar to #33218, build artifacts were being uploaded into a CarrierWave
temporary directory in the Rails root directory before moved to their
final destination, which could cause a copy across filesystems. This
merge request refactors the work in !11866 so that any uploader can
just override `work_dir` to change the default implementation.
Closes#33274
The following was happening:
1. Workhorse stores an LFS file in /var/opt/gitlab/gitlab-rails/shared/lfs-objects
2. CarrierWave then renames the file to a temporary directory (e.g. /opt/gitlab/embedded/service/gitlab-rails/tmp)
3. CarrierWave then renames the file to its final location (e.g. /var/opt/gitlab/gitlab-rails/shared/lfs-objects)
When the LFS upload path was on a different filesystem than the Rails
installation, step 2 could take a longer than 10 seconds, at which point Workhorse
would time out with "badgateway: failed after 10s: context canceled".
This change makes the work path in the same root as the LFS storage path, preventing moves
across filesystems.
Closes#33218
