[Vis Builder] Add drag and drop to main canvas

[ashwin-pc]

Add the ability to drag any field onto the main canvas and generate visualizations. When a user drags a field into the main canvas, we should be able to determine an combination of fields and aggregations that make sense for the user. They should be able to refine this further but the UI should still show them a visualization with the first field thats added.

Tasks:

• [VisBuilder] Drop field on workspace research spike #2826