provider: Add support for SignMessage and VerifyMessage API for RSA

Add support for the new EVP_PKEY_sign_message_xxx() and
EVP_PKEY_verify_message_xxx() API with combined digest and sign
algorithms such as 'RSA-SHAxxx'.

Note that RSA-PSS is not supported by this API.

This new API was added with OpenSSL 3.4.0 and requires changes in the
providers to support it.

Signed-off-by: Ingo Franzki <ifranzki@linux.ibm.com>

Author: ifranzki

src/provider/p_ibmca.h

@@ -226,6 +226,8 @@ struct ibmca_op_ctx {
                 int saltlen;
                 struct ibmca_pss_params pss;
                 EVP_MD_CTX *md_ctx;
+                unsigned char *signature;
+                size_t signature_len;
             } signature; /* For operation EVP_PKEY_OP_SIGN/VERIFY */
         } rsa; /* For type EVP_PKEY_RSA and EVP_PKEY_RSA_PSS */
         union {