WIP: Add support for MMS into purple-mm-sms

The above MR adds support to recieve and send MMS into purple-mm-sms. The code is not very well inegrated with chatty, so work is needed to add that. Receiving works for (seemingly) any file, and works to send text on a group MMS. There is stubbed out code to add things like pictures/attachments, but since chatty does not support this, I kept that code commented out. The MR is dependent on the below mmsd:

https://source.puri.sm/kop316/mmsd/-/tree/ModemManager

There is additional work needed to fully integrate it as well, but it is in a state for others to help test the recieving portion.

./bootstrap-configure --enable-debug --enable-maintainer-mode

Make it. Run daemon in foreground with debugging

./src/mmsd -n -d 'src/*'

mmsd now automakes a config file you can populate (in ~/.mms/any) for your mmsproxy, mmsc, and interface.

make and sudo make install purple-mm-sms

Run chatty (preferrably in debug mode) and test!