[keycloak-user] Reverse proxy calling admin API

[Christian Bauer]

Already done. I don't think that affects HttpServletRequest#getRequestURL(), which is what Resteasy is using to populate UriInfo#getBaseUri()?

> set the proxy-address-forwarding="true" for the http-listener.
> 
>> 
>> The proxy makes a call to Keycloak with a Bearer token and the correct X-Forwarded-* headers. Keycloak/Wildfly is configured with proxy-address-forwarding=true.