[quantization] SDNQ core loading (#14277)

* initial

* fix code quality

* dependency test fix

* apply review suggestions

* add extras and version check

* fix gating and prefer local cache for modular

* simplify transformers registration and make the version warning silenceable

* remove pipeline level test

* only model level testing

* layers to quantizze, change em dashes

* env flag for transformers

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Co-authored-by: Sayak Paul <spsayakpaul@gmail.com>