add tracking of audio and video play events

[wgilling]

This ticket encompasses tracking in Matomo custom "events" when there are interactions with players.

• play on video
• play on audio

Matomo event documentation: https://matomo.org/docs/event-tracking/
Video on play event to hook into: https://developer.mozilla.org/en-US/docs/Web/API/HTMLMediaElement/play_event

NOTE: remote_video can not be supported in the same way since the

Also, tracking PDFjs and Openseadragon were reviewed for the potential to track an event there, but it doesn't seem useful at this point to track "Zoom level change" or "pages turned" at this time. Tracking the item's PDF "view" event is handled already by Matomo if the route to the viewer is separate from the item overview page route such as "node/123/view".