Document the different ways of avoiding TLS requirements

[djeebus]

Scenarios that I can think of:

• ArgoCD doesn't have a valid certificate
• ArgoCD is listening via plaintext

It seems that recent changes have necessitate setting an additional environment variable (GRPC_ENFORCE_ALPN_ENABLED) but I'd like to make it clear when these are necessary, or simply set the env var in code when necessary based on other configuration flags.

[Greyeye]

just my two cents. most of these TLS hiccup was because of the local development. I don't think it's ideal for us to even encourage the idea of plaintext communications in other places.

[djeebus]

That's a fair point re: plaintext, although I don't think we can control whether people have set up argocd in a way that requires it.

Invalid certificates are going to come up a lot though, either when self hosting argocd or communicating with the repo server internally.