Add on HstSiteMapItemConfiguration access to the possible HstSitemapItemHandlers

This way, we can avoid:

HstSiteMapItemHandlerConfiguration handlerConfig = mount.getSiteMount().getHstSite().getSiteMapItemHandlersConfiguration().getSiteMapItemHandlerConfiguration(handlers[0]);

but just right:

resolvedSiteMapItem.getSiteMapItemHandlerConfigurations();