Update comment about required modules in extra configuration files.

Mostly adding the information to the vhost and ssl files,
and adding mod_authz_core and mod_authz_host (for
"Require all denied" and "Require all granted") where needed.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@954816 13f79535-47bb-0310-9956-ffa450edef68