initial docs for SNPE EP (#11705)
* SNPE EP docs
* minor corrections
* fixes
* c++
* remove
* Update docs/execution-providers/SNPE-ExecutionProvider.md
Co-authored-by: manashgoswami <magoswam@microsoft.com>
* review comments
Co-authored-by: manashgoswami <magoswam@microsoft.com>
