Datapackage-pipelines-metrics

* minor fixes

* Package for Python 3

* Added `append_metrics` function which allows to integrate for projects with existing source spec

* Only InfluxDB backend is supported
* row and resource metrics
* grouped by datapackage and resource names
* optionally - grouped by custom metric tags
* support batching of row metrics (defaults to 100 rows per batch, customizable)
* Example docker-compose setup including InfluxDB and Grafana for visualizations