[keycloak-dev] UI pulled from IdentityBroker

I've pulled in the Admin UI from IdentityBroker. It's updated to match the current details required for applications and realms, including support for roles and role mappings. For the time being it uses a dummy REST endpoint that is defined in the UI module itself, so it's possible to try it out and play with it, but it obviously won't configure the actual Keycloak server at the moment.