Enrich the levels allowed in hierarchical Campaigns report

The current campaigns report has two-level-hierarchy.

This request is to make it three levels at least, to take advantage of Matomo's useful campaign labeling. (Matomo allows campaign tag to have a keyword, a adgroup, an id, a campaign name. Those could be levels.)

Start by locating the hierarchical campaigns report and tracing how its current two levels are assembled. Determine how campaign keyword, adgroup, id, and campaign name are represented, then define the hierarchy needed for at least three levels. Done means the report displays the additional level consistently with existing campaign data and report behavior.

Written by the indexing model from the issue text.