As a user I want to have possibility to backup pulp when using external DB.

[ematusik]

Is your feature request related to a problem? Please describe.
I'm trying to run pulp backup from CR, unfortunately it fails on Postgres backup step.
In documentation I found that external postgres DBs backup is not avaialble at the moment.

Describe the solution you'd like
I want to have a possibility to make backup of entire pulp except of DB or make it possible to backup external db.

Source: https://pulpproject.org/pulp-operator/docs/admin/guides/backup_and_restore/00-overview/

backup/database.go:48 Failed to run pg_dump {"error": "command terminated with exit code 1"}