Remote clusters landing page to describe auth models and modes #2064
Description
The landing page of remote cluster lacks of important and relevant information about remote clusters that is only available in the self-managed part of the docs.
Security models (authentication methods), and modes should be documented in the landing page, with proper explanations.
These are relevant to all deployment types, and we should describe that TLS certificates method is deprecated and we recommend to configure remote clusters with API keys when possible.
Also connection modes (sniff & proxy) description makes sense at the landing page level, explaining that sniff method is only supported for self-managed deployments. Orchestrated deployments only support (and recommend) proxy mode for remote clusters configuration.
Only the self-managed version of the doc (/deploy-manage/remote-clusters/remote-clusters-self-managed.md#remote-clusters-security-models) has the appropriate description of security models + modes.
Once we improve this, we should be able to link from other parts of the documentation to the landing page for a description about auth models, or when needing to highlight that TLS certificates auth method for remote clusters is deprecated. We cannot do that today as the info is sin the self-managed doc.
This has been discovered while reviewing #2063