WIP: MMS support

This MR isn't intended to be merged.

It's created to be a beacon for pmOS users to test and validate MMS emission and reception until all projects are updated upstream.

Big thanks to @kop316, @sadiq and to everyone else working on making MMS a reality on Linux.

Here are the latest apk and install instructions to test MMS with mmsd and Chatty native support:

(updated: 2021-12-10)

• Install mmsd-tng from edge:

apk add mmsd-tng

• Install apk from this MR:

mkdir sms_apk

wget -P sms_apk/ https://gitlab.com/BobbyTheBuilder/pmaports/-/jobs/1871358840/artifacts/raw/packages/edge/aarch64/chatty-0.5.0_git20211210-r0.apk

apk add sms_apk/* --allow-untrusted

• Reboot your phone

• Edit/review MMS URL, APN and Proxy values in Chatty ( Option Menu > Preferences > SMS and MMS Settings)

• Reboot your phone if you made any changes