Grid shift-click range selection

[rolfsmeds]

Describe your motivation

Selecting a range of rows in a Grid by

1. selecting the item at one end of the range
2. while holding shift, selecting the item at the opposite end of the range

Describe the solution you'd like

As the Grid's lazy-loading virtual-scrolling nature means that the Grid itself often cannot known which items actually exist between the ends of the range, the only fully reliable way to implement this would seem to be a way to provide the developer with a way to implement the selection themselves when such a range-selection happens, e.g. via events.

Describe alternatives you've considered

No response

Additional context

This is basically a narrowed-down version of #2041 that focuses solely on range selection via shift-click using the normal multiselect checkboxes in Grid. (For other features like a multi-selection mode that works without checkboxes, see that other issue).