Dockerize m3aggregator and m3collector and integrate for clustered downsampling

[robskillington]

To demo this you can use the following:

cd ./scripts/development/m3_stack
AGGREGATOR_PIPELINE=true ./start_m3.sh

Then in a loop you can emit some metrics through the pipeline to see aggregated metrics flowing:

while true; do sleep 0.05; curl http://localhost:7206/api/v1/json/report -X POST -d '{"metrics":[{"type":"gauge","value":42,"tags":{"__name__":"foo_metric","foo":"bar"}}]}'; done

You can then visit Grafana and setup a Prometheus data source to hit the coordinator directly at http://localhost:7201 with type "Browser" so that direct connection to the coordinator is made without trying to proxy through the docker compose backend network.

Then try to query for foo_metric and you should see some results.

[richardartoul]

LGTM