Add a metrics collector service

Current situation

We have a collection of services that produce telemetry. That's great. But the image we produce for now is unique (allinone). So, if we want to use the telemetry produced by the services it contains, we have to configure our metric grabber (prometheus or whatever) so that it listens to a series of ports. And we have to configure our monitoring dashboard to use multiple datasources, possibly.

This is tedious.

Desired outcome

A service, running in the allinone image (if telemetry is enabled for at least one service), that collect the metrics and expose them.