- Generated password must now be named and are stored, so they are re-used on following
restarts. Password size can now be specified.
- New `not` filter for `!libervia_param` to inverse a boolean value.
- Former `front_url` field has been renamed to `web_url_path` as it is the URL path used
for web frontend. All Web frontend related field are prefixed with `web_`.
- `front_url` is now used to specify a whole front URL (notably useful if an app uses its
own domain). A list can be used to retrieve a key, like for `url_prefix`, and `https`
scheme is added if no scheme is specified.
- An abstract class is now used for App Managers.
- Last application start time is stored in persistent data.
