Telit #BND command management refactored

And added support for several new things, including:

• Setting "any" band now attempts to set all supported bands.
• Added new 2G band value '5' (egsm+dcs+pcs+g850).
• Setup support for two different 3G band combinations, a default one plus an alternate one applicable to the LM940/960 models only. The alternate combination is selected via udev tags.

During the refactor, the following Telit-specific helpers were also removed and exchanged with more generic counterparts.

• mm_telit_bands_contains() -> mm_common_bands_garray_lookup()
• mm_telit_get_band_flags_from_string() -> mm_parse_uint_list()