[keycloak-dev] Remove realm json at "/auth/realms/<realm name>"

[Stian Thorgersen]

I propose we remove the realm json returned at "/auth/realms/<realm name>"
and just return an empty page

* It can end-up being visible to end-users - we should rather have a realm
welcome page / SSO landing page here
* It's not used by anything AFAIK
* From time to time people complain about it (
https://issues.jboss.org/browse/KEYCLOAK-5279 for instance, there's more
similar issues reported)