Support pinch zoom and XY drag gestures

[angrave]

To better support low vision (and mobile users) it would be useful to easily zoom, and move around the primary video. There is already support for zooming and translating built but. A double click might reset the zoom and translation. Translation should be constrained so edge cant significantly exceed the display area).
For wide screens a vertical zoom control on the lower control bar would be useful.

Support pinch zoom and translation (multi-touch) gestures on primary video. See
http://devdoc.net/web/developer.mozilla.org/en-US/docs/Web/API/Pointer_events/Pinch_zoom_gestures.html

Add vertical slider control for rapid change in zoom magnification, which opens after clicking a zoom icon on the lower left side, next to the volume. e.g., one of these-
https://mui.com/material-ui/material-icons/?query=zoom