SYCL: Q8_0 DMMV ESIMD and MMVQ wide load (#29186)

* Adding wide-load mmvq for Q8_0 and esimd dmmv for q8_0

Assisted-by: Codex

* remove guard for q8_0

* remove docs

* Simplify by committing to clean code without fallback

* Add feature flag as requested

Assisted-by: Claude Opus 5

---------

Co-authored-by: cwriter <cwriter@localhost>