The realm named here is where keycloak-configure creates every platform
client and the cluster-admin role, and where dashboard users sign in. Naming
master puts all of that inside the realm that holds the Keycloak super-admin,
and publishes its login page wherever the platform realm is published — and
the guard belongs where the value is set, since the Keycloak chart only reads
it once a separate admin hostname is configured.
Assisted-By: LLM
Signed-off-by: Kirill Ilin <stitch14@yandex.ru>