[keycloak-dev] Hide internal clients and roles

I propose we add an attribute 'kc_internal' to internal clients (security-admin-console, master-realm, account, broker) and hide these from the clients table. We should also do this to internal roles 'admin' and 'create-realm' so these roles are not displayed in realm roles list. They would only be hidden from this page, but still be visible in user role mapping, scope mappings and default roles.