Create the base persistence system

GROOM ME: This may to be broken down into smaller stories.
It is however attached to an Epic now.

This involves something like:

• Systemd launching persistence administrator (daemon)
• Defining a partitioning scheme with writable partition
• Mounting said partition at appropriate location
• Deciding and setting up the database storage (part of "common object"?)
• Defining a couple of (abstract) logical persistence database IDs for client programs to use when accessing persistence through the persistence client library.
• Configuring the datbases to use different paths within the storage space.
• ... possibly other configuration and work which the persistence experts can probably clarify.