Merge r1351020, r1370466 from trunk:

Add new directive LuaAuthzProvider to allow implementing an
authorization provider in lua


There is only one global provider name space, therefore allow
LuaAuthzProvider only in global scope.

Remove unnecessary server config field.

Submitted by: sf
Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1374252 13f79535-47bb-0310-9956-ffa450edef68