Prepare EVP_MAC infrastructure for moving all MACs to providers

Quite a few adaptations are needed, most prominently the added code
to allow provider based MACs.

As part of this, all the old information functions are gone, except
for EVP_MAC_name().  Some of them will reappear later, for example
EVP_MAC_do_all() in some form.

MACs by EVP_PKEY was particularly difficult to deal with, as they
need to allocate and deallocate EVP_MAC_CTXs "under the hood", and
thereby implicitly fetch the corresponding EVP_MAC.  This means that
EVP_MACs can't be constant in a EVP_MAC_CTX, as their reference count
may need to be incremented and decremented as part of the allocation
or deallocation of the EVP_MAC_CTX.  It may be that other provider
based EVP operation types may need to be handled in a similar manner.

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/8877)

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