Improve Ribbon archive/fraction API

Currently, we have

.as(RibbonArchive.class).serviceName("foo")

It would be good if we took the service-name from the archive name, and more generally just had an .advertise() flag.

Additionally, some easy way to advertise something such as the keycloak-auth.war, where we don't construct the archive. Perhaps additions to the RibbonFraction of things-to-advertise.