MM logging improvements
Including:
- New log level logic:
- The old INFO level is renamed to MSG.
- A new INFO level is added with more verbosity than MSG but less than DEBUG.
- Log important user requests received via DBus.
- Requests that are unauthorized or invalid in some way are ignored.
- Requests for operations that don't change the state of the modem are not logged, with some exceptions.
Edited by Aleksander Morgado