WIP: kwinwrapper: launch kwin with specific backend depending on situation

Needed for postmarketOS to support all various 150+ booting devces zoo.

For mainline kernel based devices (or generic x86 desktops) with DRM GPU driver support is detected by /dev/dri directory presence.

For libhybris-based devices presence of /usr/lib/libhybris-egl directory is the sign.

All other devices will use software rendering on framebuffer (which will be of course slow, but "good enough for demo").