Syncplay docker with docker-compose, self-maintaining Let's encrypt TLS support and traefik enabled.

This work is based on the syncplay-server docker image. It expands its capabilities with support for traefik proxy and automatic TLS cert generation.

Copy .env.dist to .env and set desired password, (sub-)domain name, server salt and path to traefik's Let's encrypt path containing the acme.json. Start container with docker-compose up -d. Port 8999 is baked into the docker image and not modifieable. Let's encrypt cert chain is automatically split and stiched into the required files (cert.pem, chain.pem and privkey.pem) with proper UID and GID.