This implements a new Karafka subscriber that monitors more relevant
events. The subscriber will then emit events and metrics where
applicable.

This also includes new configuration parameters that let you enable and
disable Karafka specific Insights data. These are enabled by default.

```
karafka:
  insights:
    events: [boolean] # allow plugin to emit events from monitor
    metrics: [boolean] # allow plugin to emit metrics from monitor
```