Enable multiple paths to be mapped to same REST servlet

Born out of issue RESTEASY-2650, it is possible in the web.xml for a user to map a servlet to multiple paths. The currently proposed code changes for 2650 only allow a single mapping (i.e. one path for each restful servlet), but it might be nice for users to be able to specify multiple mappings for the same servlet.

This should be considered a minor enhancement since users could specify multiple servlets, each mapped to their own single path as a workaround.