attempt xformers hijack attention

WIP large refactor to make finetune script a little more manageable (#3)

add support for alpaca reflect training (#2)

Tokenization open assistant (#1)

suppport for alpaca-like instruction datasets without inputs

casts the prepared data to int16 (doesn't help with training memory)

4bit quantized support (wip)

various bugfixes

config chooser, update readme instructions, device config, llama flash attention, debug out the labels, fix config key checks, other bugfixes

black formatting

make it work with pythia in the cloud

WIP for axolotl trainer