Batou-ext

- A new component `batou_ext.systemd.ScalableService` has been added. This provides configurations
for a service that can exist multiple times (e.g. queue consumers). Detailed usage instructions
and further information can be found in the component's docstring.

- A new component `batou_ext.mail.Mailpit` has been added.
Mailpit is an alternative for Mailhog which is not maintained anymore.

- fix a mysterious regression that cause a test to fail

- redis.Redis: Allow to set provide name

* The `SymlinkAndCleanup` internally uses the `DeploymentTrash` component internally which
deletes old code using `systemd-tmpfiles` and throttles the operation with `IOReadIOPSMax`
and `IOWriteIOPSMax`.

This didn't have any effect before because these settings were wrongly placed in `[Unit]`
instead of `[Service]`.

- fix a regression in the versions update script where the environment was not loaded correctly

- `ssl.Certificate`: Set proper ACL for non-let's encrypt certificates.

- Fix setting acl for `ssl.Certificate` during ceritificate renewal.

- Set correct acl for `ssl.Certificates` on certificate renew.