improve CUDA cpy memory bandwidth when copying transposed tensor (llama/16841)

improve CUDA cpy memory bandwidth when copying transposed tensor (llama/16841)

* WIP

* added a cpy kernel specific to transposed tensor which uses smem to avoid uncoalesced access; test cases also added shwoing improved memory bandwidth

* added BF16 support

* more strict check to make sure src0 is a transpose

* reformulated to handle more complicated transpose cases

* bring back 2D transpose for higher performance

* allow build on windows

* tranpose copy more shapes

* minor tweak

* final clean up

* restore some test cases

* keep only the kernel for true tranposed case; updated with review suggestions

* make CI happy

* remove headers not needed

* reduced bank conflicts for fp16 and bf16

* add missing const*

* now bank conflicts free

* use padding instead of swizzling

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Co-authored-by: bssrdf <redacted>