Shared PostgreSQL Database Hosting Setup

* Manage cluster only via access to a super user account
- no permanent modification of pg_hba.conf etc. required
- central managing system can manage several clusters without the need for additional control channels
* Customers cannot directly create new roles and databases
* Each customer database is given an associated main user
- acting as a database local super user
- typically creates and owns all objects
* The can be a number of additional users per database
- Rights of these users are granted by the main user