use sni-based routing with nginx for web,api,caldav, and carddav

[flaviomartins]

the self-hosting setup exposes the web container via port 443.

the proposed changes adds nginx as a pass-through proxy that exposes the REST/WebDAV containers on port 443 based on the prefix subdomain obtained via SNI

Checklist

• I have ensured my pull request is not behind the main or master branch of the original repository.
• I have rebased all commits where necessary so that reviewing this pull request can be done without having to merge it first.
• I have written a commit message that passes commitlint linting.
• I have ensured that my code changes pass linting tests.
• I have ensured that my code changes pass unit tests.
• I have described my pull request and the reasons for code changes along with context if necessary.

[titanism]

@flaviomartins did you have this running and tested on your self hosted setup?

[flaviomartins]

@titanism I did have this running before. I believe this was the only way to have everything work using a single machine (multiplexing on the same HTTPS port). Let me know if it needs more work.