Rat uses collections of URLs which are reported as a problem by spotbugs

As noted in the Spotbugs documentation:

Dm: The equals and hashCode methods of URL are blocking (DMI_BLOCKING_METHODS_ON_URL)

The equals and hashCode method of URL perform domain name resolution, this can result in a big performance hit. See http://michaelscharf.blogspot.com/2006/11/javaneturlequals-and-hashcode-make.html for more information. Consider using java.net.URI instead.

The goal of this ticket is to change all stored URLs to URIs.  The primary change is in the ReportConfiguration but it will touch both UIs and the core classes.