SSL Trace improvements

A fix formatting fixes.

SSL Trace: internal constification
-  static trace tables
-  trace methods arguments

SSL Trace: enhance error message when tracing an invalid extension packet
... instead of just "Message length parse error!".

SSL trace: add Maximum-Fragment-Length TLS extension log support

Reviewed-by: Andy Polyakov <appro@openssl.org>
Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/4353)