mod_ssl: Propose a more modern Cipher and Protocol list, honor server cipher

priority and add explanations relative to RFC 7525 guidance.

Submitted by: wrowe
Backports: 1679428, 1679432 
Reviewed by: wrowe, ylavic, rjung



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@1681002 13f79535-47bb-0310-9956-ffa450edef68