Move AutoPadType to common.h (#4474)
Extracting some common code related to "AutoPadType" from the cpu execution provider into "common.h".
Motivation and Context
* Sharing code with authors of other execution providers that need the same functionality.
* I didn't modify the code in shared_library or dnnl EP to avoid changing their dependency structure, so there is still a redundant copy of the AutoPadType code in there.
