cleanup provider digests

cleanup provider digests

Added some missing #ifdef NO_XXX around some of the digest functions.
Renamed core_mkdigest.h to digestcommon.h
Added ERR_raise() to set/get params for digest.
Moved common code for get_params/gettable_params into digest_common.c
Renamed #defines in digestcommon.
Removed null_prov.c (It should not be needed)

Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/9625)