SSDM-2824: Reference to DTD removed because Jetty wants to read it from the...

SSDM-2824: Reference to DTD removed because Jetty wants to read it from the URL which leads to a time out on our CI server.

SVN: 38196

openbis_standard_technologies/resource/server/jetty-web.xml

 <?xml version="1.0"  encoding="ISO-8859-1"?>
-<!DOCTYPE Configure PUBLIC "-//Jetty//Configure//EN" "http://www.eclipse.org/jetty/configure.dtd">
  
 <Configure class="org.eclipse.jetty.webapp.WebAppContext">
 	<!-- Allow symbolic links  -->