Add functor- and function-based kernel registration API (#18162)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/18162
- Adds the API to register a functor- and function-based kernel.
- Change the experimental c10 ops to use this new API instead of the old one
- Deletes the old APIs in KernelRegistration.h and OpSchemaRegistration.h
Reviewed By: dzhulgakov
Differential Revision: D14514239
fbshipit-source-id: 35b2f6e8f62964e54886450a6a5fac812ed20f26
