Simplify Auth-bundle config

[vvondruska]

Adjust the auth-bundle configuration, so that it fulfills the following requirements:

• be able to provide values in a single place and without worrying about labels etc (I got errors because of labels/annotations missing)
• be able to infer the MC name in athena without having to pass an additional configmap
• have the two values specified in dex being the default (not sure if it already is)
• in other words, I think we should ask customers to only provide the real configuration without having to deal with all the underlying shenanigans (cluster CR, annotations for app-operator, ...) that our platform uses under the hood. as a managed service we should take care of the shenanigans and they should just consume the platform