* add: initial script to train clm fim
* fix: if training model from scratch, new tokens will be added and embeddings resized
* fix: fixed attention_mask errors when generating FIM data
* fix: file formatted using black
* add: run_fim_no_trainer.py and fixed some comments in run_fim.py
* add: added fim examples to the README.md and ran code fixup
* fix: little bug in both fim training scripts
* fix: remove comment from notebook and added a note on fim related params
* fix: minor typo in README
* add: suggested minor changes to README and run_fim.py
* add: gradient_accumulation_steps and gradient_checkpointing args
* add: improved model embedding resizing
* add: pad_to_multiple_of and attn_implementation params
* add: requested minor changes
* add: deepspeed zero compatibility
* add: resize embeddings layer with zero3 support for fim model initialization
