Add Garagen

[klawr]

Created by: klawr

Problem Description
Garagen are added by including them in the Vertrag.
Garagen may be part of the Vertrag, but they can be separate, too.
They are however not relevant for the Betriebskostenrechnung.
We have no overview of available/occupied garages with respective costs

Proposed Solution
Add Garages. They may be occupied by a Vertrag regarding a Wohnung, or a special GarageVertrag