{8} Collect Actyx metrics from HTTP endpoint

### Job story

When:

- I operate an Actyx solution consisting of multiple nodes

I want to:

- Include Actyx metrics in my monitoring system

So that:

- I can set up alarms for Actyx metrics
- In case of alarms or incidents, I can monitor how specific Actyx metrics have behaved over time

### Acceptance criteria [WIP]

- [ ] Actyx provides an endpoint that can be polled by Prometheus
- [ ] Metric for connected peers
- [ ] Metric for known peers
- [ ] Metric for performance of Actyx / duration of queries
- [ ] Metric for log errors
- [ ] Metric for API errors
- [ ] Metric for storage used by Actyx
- [ ] Memory/CPU used by Actyx
- [ ] Each metric should be labelled with
- [ ] Node ID
- [ ] Display name