This adds some very simple metrics to all of the background jobs that
consume the event streams. Currently, the only "real" metric is a
counter tracking how many messages have been processed by that consumer,
but a lot of the value will come from being able to utilize the
automatic "up" metric provided by Prometheus to monitor and make sure
that all of the jobs are running.
I decided to use ports starting from 25010 for these jobs - this is
completely arbitrary, it's just a fairly large range of unassigned
ports, so shouldn't conflict with anything.
I'm not a fan of how much hard-coding is involved here for the different
ports and jobs in the Prometheus config, but it's also not a big deal.
Deimos