Batou-ext

- `oci.Container`: Add option to disable OCI container monitoring.

This is mainly useful for containers which are not running all the time.

- `oci.Container`: make rebuild optional

This is useful, when there are multiple container deployed which should be activated at once.

- Fix a bug in the version update script where multiple environments sharing the same branch would not be updated correctly

- the `SymlinkAndCleanup` component was adjusted to clean up asynchronously using systemd's tmpfiles instead of deleting all candidates immediately

- oci.Container: Fix a bug where containers were not restarted properly even though their image digest was out of sync after the remote tag has been updated

- oci.Container: Fix a typo in the oci container component's verify method

- `batou_ext.python.FixELFRunPath`: search not only `env_directory`, but also its subdirs for C libraries needed by the libraries to patch.

- Fix `PurgePackage` raising error when package is not found.

- The attribute `public_smtp_name` of `batou_ext.mail.Mailhog` now has a default value. It points to `self.host.fqdn`.

- adjust the certificate expiry check output to be more easily parseable

- systemd timers: add an option to enable persistence
breaking change: systemd timers are now non-persistent by default.
The previous default behaviour was a problem for cronjobs that should
not be started immediately following a reboot / downtime

* Added a component `batou_ext.python.FixELFRunPath` which modifies `DT_RUNPATH` & `DT_RPATH` of `.so`-files in a venv to load the correct libraries (from either a Nix env or other Python libraries). Please read the docstring carefully before using it.

- OCI: cache validation result during deployment.

Caching results speeds up deployments where multiple containers with the same image are deployed.

* 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`.

- OCI: Support registries where the docker login is different than the registry used in referencing containers.

- OCI: Improve change detection of remote images (required for docker.io)

- OCI: The nix file does not contain sensitive data, so don’t mark it as such.

- OCI: add support for extraOptions

* Added a script `s3_bootstrap` that interactively creates an S3 bucket (including a radosgw account & keys if needed). Will be installed with `batou_ext` if the `s3-bootstrap` extra is requested.