pgdg-keyring package is pgpg repository, install it separately
Support apt.postgresql.org version specific packages.
Add manage_postgresql_conf flag to avoid config customization
register the new cluster after initdb to distribution scripts

Make the new created cluster know to Debian/RHEL scripts.

This will ensure that postgres will be restarted correctly on boot.

On Debian/Ubuntu if you are using postgresql-common => 142 it will also
allow to create the cluster in a non standard location disabling the
autocreation of cluster on install when run_initdb parameter is set
Add support to custom xlogdir parameter to postgresql::initdb