Configure container registry in gprd to use the metadata DB

After confirming the registry patroni DB cluster in production is complete (#2021 (closed)) we can configure registry in canary and production to make use of the metadata DB.

Config should look like this:

registry:
  database:
    enabled: true
    host: pgbouncer-registry.int.gprd.gitlab.net
    port: 6432
    user: gitlab-registry
    name: gitlabhq_registry
    connecttimeout: 5s
    draintimeout: 15s
    password:
      secret: registry-postgresql-password-v1
    pool:
      maxopen: 30
      maxidle: 15
      maxlifetime: 30m
      maxidletime: 5m
  migration:
    enabled: true
    rootdirectory: gitlab
  storage:
    secret: registry-storage-v4
  maintenance:
    uploadpurging:
      enabled: false

The pool maxopen and maxidle settings are subject to testing and benchmarking of course.

And we need to make sure that the registry-postgresql-password-v1 is deployed to the gprd deployments.

And make sure the DB password doesn't contain special chars like @ (gitlab-org/charts/gitlab#2889 (closed)).

Status Update 2021-11-03

The CR was executed successfully. The registry DB is enabled in production since 11/02.