mod_autoindex: new directive IndexStyleSheet

PR:
Obtained from:
Submitted by: Tyler Riddle <triddle_1999 yahoo.com> and Paul Querna <chip force-elite.com>
Reviewed by:


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@101809 13f79535-47bb-0310-9956-ffa450edef68