* fix(webconnectivity): expose network events
By not exposing network events in webconnectivity, we are missing
several interesting, explanatory data points.
This diff fixes the issue by:
1. enriching the definition of network events to include extra
data useful for performing (manual) data analysis;
2. adding a tags field to network events such that we can add
tags to specific events and understand where they come from;
3. exposing all the (tagged) network events that happen when running
a webconnectivity experiment.
See https://github.com/ooni/probe-engine/issues/1157.
* progress
* more work towards landing this diff
* Apply suggestions from code review
fc19c9901a