docs: No Explanation on how to enable TLS without terraform

I was looking for some docs about how to enable TLS in an existing deployment. This page gives an overview about what happens on an architectural level, but does not give me anything to work with. There's some terraform example, but not everyone uses that (yet).

Please add an example on how to enable TLS.

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*Reported from: https://documentation.ubuntu.com/observability/track-2/how-to/configure-tls-encryption/*

Start with the configure-tls-encryption page linked in the report and compare its architectural overview with the existing Terraform example. Add a concrete example for enabling TLS in an existing deployment without Terraform, then verify that the documented steps are complete and understandable.

Written by the indexing model from the issue text.