Add external compose support in the docker role

- Use ansible.posix.synchronize for compose.yml
- Set fact for compose service restarts
- Introduce plain Docker dev host
- Optionally verify repos via GPG before sync
- Hide docker_repos_path in .folder
- Tweak .env for conciseness
- Add --diff to Ansible in Vagrantfile
- Clean output with loop_control
- Embed GPG in base role

roles/docker/defaults/main.yml

@@ -3,4 +3,4 @@ docker_compose_service: compose
 docker_compose: /usr/bin/docker-compose
 docker_repos_keys: "{{ docker_repos_path }}/.keys"
 docker_repos_keytype: rsa
-docker_repos_path: /srv/compose_repos
+docker_repos_path: /srv/.compose_repos