Gitaly-on-NFS staging test plan

How will we test this on staging with 9.1. RCx.

make sure Gitaly over TCP works in omnibus
test with localhost
test with remote host and different repository root
instructions to prepare staging
wait for package with all required capabilities to be deployed on staging
schedule time with someone with production access to run experiments on staging

Parallel production issue: https://gitlab.com/gitlab-com/infrastructure/issues/1777

Merge Request with (some of) the required staging configuration changes https://dev.gitlab.org/cookbooks/chef-repo/merge_requests/637

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information