Enable many gpu72 options

Add support for:

* Fetching LLTF or DCTF work
* Fetching work by GHz-days instead of number of assignments
* Fetching work by what_makes_sense (default), lowest TF level, highest TF level, lowest exponent, oldest exponent, no P1 done (DCTF), LHM bit-first (LLTF), LHM depth-first (LLTF), and let GPU72 decide.