[Hardware][CPU] Support chunked-prefill and prefix-caching on CPU

[bigPYJ1151]

This PR provides CPU chunked-prefill and prefix-caching support. For now only FP32 and BF16 are supported, ipex-2.6 will provide the FP16 support.

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[DarkLight1337]

Can you define this mark in pyproject.toml?

[DarkLight1337]

We may need to increase the timeout, I think 25 minutes isn't enough now.

[DarkLight1337]

I'll leave the detailed review to @Isotr0py and @WoosukKwon .

[Isotr0py]

Since FP8 KV cache is still under development, perhaps we can keep this note temporarily.

[Isotr0py]

Can we separate the contents of this "if else" statement into two functions like _compute_prompt and _compute_decode? I think this if else statement is a little bit too long.

[Isotr0py]

Suggested change

	data.input_mrope_positions[0].extend( # type: ignore
	next_pos[0])
	data.input_mrope_positions[1].extend( # type: ignore
	next_pos[1])
	data.input_mrope_positions[2].extend( # type: ignore
	next_pos[2])
	for idx in range(3):
	input_mrope_positions[idx].extend(next_pos[idx])

I think we can keep the previous for loop here to avoid duplicate code.

[Isotr0py]

Suggested change

	self.input_data.input_mrope_positions[0].extend( # type: ignore
	mrope_positions[0])
	self.input_data.input_mrope_positions[1].extend( # type: ignore
	mrope_positions[1])
	self.input_data.input_mrope_positions[2].extend( # type: ignore
	mrope_positions[2])
	for idx in range(3):
	input_mrope_positions[idx].extend(next_pos[idx])

Ditto.

[Isotr0py]

I think we should not prepare attention metadata in model runner explicitly. We can implement TorchSDPAMetadataBuilder and move these logics there (just like xformers and FA).