Add suppport to retain agent config between container redeployment with volumes

[vegiemane]

Changed the docker compose to just add a volume and was able to keep the config between deletion of the container and redeployment.

version: "3"

services:
  playit:
    container_name: playit
    image: ghcr.io/mafen/playit-docker:latest
    volumes:
      - ./config:/etc/playit
    restart: unless-stopped

[mafen]

Thanks for the suggestion, it is added in 03015c7