Add Common shared code needed to move aes ciphers to providers

Add Common shared code needed to move aes ciphers to providers

Custom aes ciphers will be placed into multiple new files
(instead of the monolithic setup used in the e_aes.c legacy code)
so it makes sense to have a header for the platform specific
code that needs to be shared between files.
modes_lcl.h has also moved to modes_int.h to allow sharing with the
provider source.
Code that will be common to AEAD ciphers has also been added. These
will be used by seperate PR's for GCM, CCM & OCB.

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/9301)