Drop HAL configuration
We've had xorg.conf.d support since server 1.8 (2010) and HAL configuration in fdi files has considered deprecated since. The device enumeration backend shouldn't matter anyway, so let's enforce xorg.conf only by dropping all mentions of HAL in this program.
cc @alanc - I'm assuming you dropped fdi configuration a decade ago or so too?
cc @tias - i think that's the only true functional change so far, I'm going to push out 0.8 after this and then probably let the project rest in peace for the next few years