Managing Argo CD access to resources and objects

Add docs on how to manage Argo CD access to perform various operations on clusters. The use-cases to cover are

• Permissions given to the default Argo CD instance (details)
• How to give access to an Argo CD instance to managed other namespaces through the managed-by label (details)
• Giving access to an Argo CD instance to managed additional resources (e.g. Kafka CRs) in the same namespace (#03151366)
• Setting up service account and rolebinding on remote clusters for Argo CD to be able to sync resources to them