Add more streamlined local and single_gpu support, allow use of 8 bit adam optimizer

[asutermo]

Tested on an Ubuntu a100 40 gb

• Provides a 1B C config
• Fixes a typo
• Allows slurm, gpu, single gpu or cpu
• bitsandbytes support for Adam 8 bit
• adds checks so FSDP isn't used in conjunction with single_gpu
• cleaned up a handful of imports