In handleCommandHelloFromRemote in DCPPacketHandlerCentralStationHello, get new client ID and sessID with central station from central station db.
Removed MAC address from command_stations and drones tables. Was useless info (at least for now).
Corrected method to retreive description in Hello from remote. Previous implementation missused fromUtf8().
Added constants for tables names.
New remote is added to db via DCPServerBackendCentral::addNewRemote(), DCPPacketHandlerCentraStationHello now stores the type of the new remote.