Adding skeleton documentation for mod_lua, and all of the associated

metafiles pertaining thereto. While this is better than nothing, it's
not *much* better than nothing, and is very probably inaccurate. But
it's a starting point.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@935894 13f79535-47bb-0310-9956-ffa450edef68