[keycloak-dev] Allow bearer-only cilents to have service accounts

Currently a bearer-only client can't have a service account and that seems like a mistake. Further this prevents bearer-only clients to use the authorization services. Is there any good reasons why bearer-only clients can't have service accounts and be able to obtain token using the client credential grant? The only thing a bearer-only client should be prevented to do IMO is authenticate users (authorization code flow and resource owner credential grant).