[GenAI] Use BitsAndBytes for 4bit quantization.

[LittleLittleCloud]

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This PR uses the 4bit quantization method from bitsandbytes library to quantize linear layer into 4 bits.

What's bitsandbytes

bitsandbytes is a library used by huggingface transformer to provide support for 4bit and 8bit quantization and operation.

The bitsandbytes is written in cuda, and we provide a C# binding library LittleLittleCloud.TorchSharp.BitsAndBytes to enable easy leverage with torchsharp library.

[LittleLittleCloud]

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/azp run

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[LittleLittleCloud]

/azp run

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