Docker: Add env vars to compose files

[stephendade]

To aid user configuration, I've added the required environmental vars to reference the server's external IP address.

I've also added some other environmental vars that a user can uncomment and use if needed.

[RadioAndrea]

I agree, but this was mostly covered in the work did earlier, merging in the working branch to main then will compare with that

[RadioAndrea]

Performed a manual merge, most of this was duplicate of work we already had in the container working branch, but I did include a few of the wordings.

I don't want to recommend people to update the IPs at the bottom of the file because we already have documentation about those, and the descriptions in the file could lead people astray if they run multiple container networks or have something like a reverse proxy in place.