Port type hints rework and new ID_MM_REQUIRED udev tag

Users with QMI or MBIM capable modems may want to ensure that these are never managed using plain AT commands, as that also involves using PPP. This fallback to AT could happen if the QMI or MBIM port probing fails for whatever reason.

The new ID_MM_REQUIRED udev tag allows specifying that a given port MUST be successfully grabbed when creating a new modem object, or otherwise the modem object will not be created at all (even if there are other fallback control ports like AT that could have been used).