* Added component `batou_ext.http.HTTPServiceWatchdog` that adds a check to a systemd unit
whether a given URL is reachable (e.g. a `/health` endpoint). If the URL cannot be reached within
a certain interval, the service will be restarted. Further details are documented in the
docstring.
- Fix `SymlinkAndCleanup` async delete and allow custom extra arguments to `systemd run`.