GitLab

This requires to implement the __deepcopy__ method in Int8Params.
Moreover, there was an issue in the Linear8BitLT constructor that would
assign instance attributes to the class, which is now fixed.

Please review carefully that this does not impact existing code.

Tests that I ran:

- pytest tests/test_linear8bitlt.py
- in PEFT: python -m pytest -m "single_gpu_tests and bitsandbytes" tests/test_gpu_examples.py
- in PEFT: python -m pytest -m "single_gpu_tests and bitsandbytes" tests/test_common_gpu.py
- in transformers: RUN_SLOW=1 python -m pytest tests/quantization/bnb -x