LFS objects and artifacts should not rely on a shared NFS file server for caching before uploading to object storage

The directories

/var/opt/gitlab/gitlab-rails/shared/lfs-objects
/var/opt/gitlab/gitlab-rails/shared/artifacts

are NFS mounts that are shared between the front-end and sidekiq fleet on GitLab.com. The directories are used for temporary storage for caching before uploading to object storage. It would benefit HA deployments if we did not have any dependency on a shared filesystem for this caching.

This is important to gitlab.com because this nfs mount is a single point of failure for gitlab.com and ties into our availability goals.