Refactor `dns dynamic` (ddclient) service configuration to address additional issues:
1. Use per-provider configuration `min-interval` to control IP address update interval instead of modifying the global `daemon` property to slow everything down. Controlling `daemon` has a few side effects:
- Installations using services like `sit` tunnels (e.g. tunnelbroker.net) might have an impact
- `daemon` configuration in `ddclient` also controls the actual Perl service that stays resident in the system. We ought to move to systemd timer anyway and avoid keeping the Perl process resident
- The slowing down the daemon doesn't serve the original intention anyway. `ddclient` would hit a provider multiple times even in single-pass because of incorrect cache data (see T5573)
2. Fix file access mode for /run/ddclient/ddclient.conf to fix warnings like:
```
Sep 09 22:51:40 ddclient[1868]: WARNING: file /run/ddclient/ddclient.conf: file /run/ddclient/ddclient.conf must be accessible only by its owner.
Sep 09 22:51:40 ddclient[1868]: WARNING: file /run/ddclient/ddclient.conf: file /run/ddclient/ddclient.conf must not be accessible by others.
```
3. Fix `vrf` configuration properly