doc: graph: add document for sdpa with compressed key and value

[wzt1997]

General

1. Add document for SDPA with compressed Key and Value

[mgouicem]

(open question) Do we want to have separate document for non-quantized and quantized patterns?
My understanding of existing SDPA page was that it would regroup different data-types given that it currently has a subsection for floating-point pattern.

[TaoLv]

(open question) Do we want to have separate document for non-quantized and quantized patterns?

Thank you @mgouicem ! That's also my question. Initially when i added the floating-point section, i was thinking to include all these fp, int8 quantized, and only kv quantized patterns together in a single page. But with this PR, it seems there will be too much information. Maybe we need @ranukund 's input for which is a better format.

[wzt1997]

Do we want to have separate document for non-quantized and quantized patterns?

Thanks for the question! From my perspective, I think it's better for us to put the quantized sdpa patterns in a separate document as it requires much more information compared with pure floating-point patterns, such as fpmath mode setting, group quantization and adding extra dynamic quantization ops.

It's also worth noting that this PR only includes the document for quantization sdpa patterns with compressed KV, but not the pure quantized sdpa. We may need to think about fusing them together in the future.

[TaoLv]

Document folder has been changed on main branch. Please rebase the PR. Thanks.

[vpirogov]

@ranukund, please help with the review.

[ranukund]

I've left a few comments, please incorporate as you see fit.

[wzt1997]

Thank you @ranukund! The suggestions are incorporated now.

[ranukund]

Few more minor edits suggested, please incorporate, thanks!

[wzt1997]

Few more minor edits suggested, please incorporate, thanks!

Thanks Ranu. I've incorporated the suggestions.