Add installation via docker compose (MVP 1)

- Add markdown tabs blocks
- Fix [Issue 604](https://github.com/chatmail/relay/issues/604)
- Add `--skip-dns-check` argument to `cmdeploy run` command
- Add `--force` argument to `cmdeploy init` command
- Add startup for `fcgiwrap.service`
- Add extended check when installing `unbound.service`
- Add configuration parameters (`is_development_instance`, `use_foreign_cert_manager`, `acme_email`, `change_kernel_settings`, `fs_inotify_max_user_instances_and_watchers`)

.gitignore

@@ -164,3 +164,9 @@ cython_debug/
 #.idea/
 
 chatmail.zone
+
+# docker
+/data/
+/custom/
+docker-compose.yaml
+.env