Add "Average Pages per visit" metric under Visitors > Overview

Currently we report "Average actions per visit" in Visitors > Overview. Actions in this case also include downloads, outlinks, and internal site searches. (see Actions in Matomo FAQ)

It would be valuable to also report "Average pageviews per visit" because often users want just the number of pageviews per metric.

Maybe we could show both metrics in the same row eg. 3.9 actions (page views, downloads, outlinks and internal site searches) per visit, 3 pageviews per visit (or could be on a new line).

The Visitors Overview currently looks like: