INSTALLER USER: Can do everything except invite/remove other "building" admin
BUILDING ADMIN: has complete management of invitations from other users, both installers and building admin
CANNOT make "structural" changes to the system:
- adding/removing apartments
- adding/removing gates
- adding/removing switchboards
- changing system parameters (e.g. SCS addresses)
NOTE: the user who creates the system will have the double role of installer and building admin