Add skeleton for the org.genivi.LUCHandler1 service implementation

Add skeleton for the org.genivi.LUCHandler1 service implementation

This skeleton has stubs for the implementation of the Register() and
Deregister() methods. It currently uses the session bus to make it
easier to test as a regular user.

The implementation does not use the DLT yet, neither does it register
with systemd's watchdog mechanism. It also does not register with the
NSM as a shutdown consumer yet.

GDBus appears to need a little help to add parameters to the generated
C functions, so we'll probably have to extend the XML interface
definition with a few annotations.