Help Wanted: Provide TLS cipher overwrite examples in documentation

[cwarnermm]

Context

Our current documentation for the TLS Cipher Overwrites is missing examples that show how to use it.

It's also unclear whether this configuration setting affects TLS 1.3.

Docs requests

1. Identify 1-2 examples that can be included in the product documentation.
2. Update the broken /model/config.go link in the second bulleted note to point to the correct location in the mattermost/mattermost GitHub repository (if it exists).

How you can help

Create a docs PR to update the documentation with these details, and to clarify that this configuration setting does NOT affect TLS 1.3.