Convert the following macros to static inline functions:
* PyByteArray_AS_STRING()
* PyByteArray_GET_SIZE()
* PyBytes_AS_STRING()
* PyBytes_GET_SIZE()
Limited C API version 3.11 no longer casts arguments.
Add _PyBytes_CAST() and _PyByteArray_CAST() macros.
Add Include/cpython/bytearrayobject.h and
Include/cpython/bytesobject.h header files.
Move CPython C API from Include/bytesobject.h into a new
Include/cpython/bytesobject.h header file which is included by
Include/bytesobject.h. Do a similar change for
Include/bytearrayobject.h.