Add callbacks supporting generation and retrieval of supplemental data entries, facilitating RFC 5878 (TLS auth extensions)

Removed prior audit proof logic - audit proof support was implemented using the generic TLS extension API
Tests exercising the new supplemental data registration and callback api can be found in ssltest.c.
Implemented changes to s_server and s_client to exercise supplemental data callbacks via the -auth argument, as well as additional flags to exercise supplemental data being sent only during renegotiation.

doc/apps/s_client.pod

@@ -45,6 +45,8 @@ B<openssl> B<s_client>
 [B<-sess_in filename>]
 [B<-rand file(s)>]
 [B<-serverinfo types>]
+[B<-auth>]
+[B<-auth_require_reneg>]
 
 =head1 DESCRIPTION
 
@@ -272,6 +274,15 @@ a list of comma-separated TLS Extension Types (numbers between 0 and
 The server's response (if any) will be encoded and displayed as a PEM
 file.
 
+=item B<-auth>
+
+send RFC 5878 client and server authorization extensions in the Client Hello as well as
+supplemental data if the server also sent the authorization extensions in the Server Hello.
+
+=item B<-auth_require_reneg>
+
+only send RFC 5878 client and server authorization extensions during renegotiation.
+
 =back
 
 =head1 CONNECTED COMMANDS