Explore options to make NFS node optional

Consistent feedback recently is users would like to remove the NFS node if possible.

Currently it's required in GET for the following:

• GitLab Incremental Logging default behaviour
• GitLab Secrets propagation
• Rails SSH keys propagation

Task is to explore simple alternatives for each above.

It's worth calling out this is tricky, especially around Secrets (where there's expected to be a product solution at some point) so the solution here shouldn't be too complicated while we await that.