Move prometheus to SaaS and make it a plugin
Move static callers to use metrics_queue plugin
Change local-docker to support different quay clone dirnames
Change prom_aggregator to use logrus
This entails writing a metric aggregation program since each worker has its
own memory, and thus own metrics because of python gunicorn. The python
client is a simple wrapper that makes web requests to it.
This change adds a generic queue onto which metrics can be pushed. A
separate module removes metrics from the queue and adds them to Cloudwatch.
Since these are now separate ideas, we can easily change the consumer from
Cloudwatch to anything else.
This change maintains near feature parity (the only change is there is now
just one queue instead of two - not a big deal).
