Add docker build files

[jacobeva]

This PR adds docker build files, along with fixing a lot of issues I discovered with minor errors in the makefiles and such. It should make building Sideband, specifically for Android, a LOT easier from now on!

[jacobeva]

This is now partially broken since Mark has pushed some local changes from his side (I was wondering where the codec2 stuff was!). I will work on fixing this in a couple weeks.

[markqvist]

Thanks Jacob, sorry about the lack of coordination! Having the docker build option would be very nice.

[regulad]

@jacobeva hey, does this still work? I'm having trouble getting it to build in a container on 24.04 because of some automake issue: https://termbin.com/k4v5