Support drag-and-drop data tables

[avmey]

Supporting dragging and dropping into the browse area would be great (if you try to do this the data actually uploads to data layers instead)

[underbluewaters]

Agree. This is super confusing. The reason it's like this is that the drag & drop library I use sets up a "DragContext" on the entire data layers admin area. It doesn't work well with multiple contexts. So this might be difficult to fix without upgrading some other dependencies.