Provide example Grafana dashboards

[ti-mo]

Currently, the project only focuses on exporting data to certain back-ends. This does not provide any quick value to the user, and makes it difficult to get started with conntracct.

Provide a collection of Grafana dashboards the user can get started with, and load these dashboards into the docker-compose stack when it starts up.

In case anyone is already interested in using the tool and lands here looking for an example query, this is a basic example for visualizing per-flow bytes in the original direction from InfluxDB:

SELECT sum("bytes_orig_rate")
FROM
(
  SELECT non_negative_derivative(mean("bytes_orig"), 1s) AS "bytes_orig_rate"
  FROM "conntracct_udp"."autogen"."ct_acct"
  WHERE "bytes_orig" != 0
  GROUP BY time(1s),*
)
WHERE $timeFilter AND ("dst_port" =~ /.*/)
GROUP BY time(1s),* fill(none)

I've read that the new Flux query/scripting language could drastically improve the way of doing this, obviating the need for a subquery on high-cardinality metrics. I would not mind if the project focused exclusively on Flux.