Add traefik support

[Uzurka]

Hello, I'm actually working on Ansible since o discovered this tool, and i have to admit this is a good deployement tool I would like to use that role to deploy my mailcow stack on my eventuals future server reinstallation (i mean we never know what can happen) Only problem is that i use Traefik for quite everything, and if traefik usage with docker-compose is quite easy, using traefik with this ansible role is a bit more complicated, as it needs to edit the compose file, add an override, and, the easiest part as this is done with env, change mailcow.conf values.

I'll probably give a look into that from time to time, in case I can do it myself, but if someone manage to do a correct PR/MR to add the ability to use Traefik, it would be really nice :D

[Uzurka]

Finally did it : https://git.uzurka.fr/Uzurka/mailcow-ansiblerole