Extract mapbox-compose to its own github repo

For the location feature on EXA, a fork of https://github.com/googlemaps/android-maps-compose to work with MapLibre has been created and now lives in the same EXA repo at https://github.com/vector-im/element-x-android/tree/develop/libraries/maplibre-compose .

As a UI library it is very hard to test so it currently contributes a lot of untested LoCs to EXA, plus it would be very good to have it as a dedicated project so that we can benefit from community development too. There are currently a few similar forks already out there in github but they didn't gain much traction. If we are able to show that our library has already been battle tested by thousands of EX users, this could probably help in establishing it as the de facto library to use for getting MapLibre to work in jetpack compose.