Provide example for HTTPS container #335
Description
So far we ruled out to provide a container that provides HTTPS (despite people asking for it, e.g. #315), because managing TLS-certificates is quite complex if it should be automatic in all ways.
But I think we could give it a new attempt if we just use Apache+mod_md or Caddy (or maybe FrankenPHP?), which do all the complicated certificate management stuff on their own. We "just" would have to write a Caddyfile that uses environment variables set from the compose-file, or extend the entrypoint-script to inject a few (one?) line(s) into the Apache config if an environment variable is set.
Of course this has potential to make problems, but on the other hand I would like to help people to provide a webmail server with proper certificates.