Use CMake

Created by: LNJ2

Just some notes (more or less for me):

Swiften cmake module (I've found on github)

https://github.com/hanzz/spectrum2/blob/master/cmake_modules/SwiftenConfig.cmake

kirigami git repo (with cmake scripts)

https://cgit.kde.org/kirigami.git/tree/README.md

This should make it easier to build apks with kirigami and to find packages like swiften. (I'm not satisfied with the current solution)