Instead of manually maintaining a list of instances that should never be prompted (like in https://gerrit.wikimedia.org/r/c/operations/puppet/+/700928), we should instead generate this list using puppet.

Now that T285390: Move sanitarium masters to dedicated puppet role is done, we can automatically exclude sanitarium master instances.

This should be doable by querying puppetdb at run-time, similar to how this CR did it for wikireplicas: https://gerrit.wikimedia.org/r/c/operations/puppet/+/627379