Unmount the shared mount /var/opt/gitlab/gitlab-rails/shared/cache across all VMs

Part of &98 (closed)

Other than gitlab-org/gitlab#39496 (closed) we have no known outstanding issues that requires this mount, which is a SPOF for all front-end nodes. We are currently working around the cleanup with a system cron

We current cache archives at cloudflare for public projects, but not private projects. We have the option of disabling the disk cache but we would need to asses the impact to Gitaly

• Set workhorse_archive_cache_disabled on staging
• Remove the mount on staging
• Set WORKHORSE_ARCHIVE_CACHE_DISABLED on canary
• Set workhorse_archive_cache_disabled on production
• Remove the mount on canary
• Remove the mount on production