Restart service when configs are removed

Previously the configs were removed from `/etc/rsyslog.d` but the `rsyslogd`
service wasn't restarted, causing any config options to remain loaded.

.. and ..

De-duplicate `require` and `notify` parameters by moving them into the
parent class where each sub-class is instantiated. A side-effect of which is
that new resources within those classes won't forget to notify/require the
relevant sub-class.