## Problem
Inbetween adding the TLS config for compute-ctl, and adding the TLS
config in controlplane, we switched from using a provision flag to a
bind flag. This happened to work in all of my testing in preview regions
as they have no VM pool, so each bind was also a provision. However, in
staging I found that the TLS config is still only processed during
provision, even though it's only sent on bind.
## Summary of changes
* Add a new feature flag value, `tls_experimental`, which tells
postgres/pgbouncer/local_proxy to use the TLS certificates on bind.
* compute_ctl on provision will be told where the certificates are,
instead of being told on bind.