Allow for runtime management of drop zones

[Cyara-Andrew-Watson]

At the moment, it would appear that the only way to specify drop-zones for drag-select, is to register them through the settings - either at startup, or using the setSettings method.

In react, it is awkward to use this interface as we need to pass a random reference array, while the management of the selectables is much easier - being able to do it inside each component as it is registered (one at a time).

What I would like is a set of methods that allows us to get/add/remove drop target elements in a similar way that we can manage selectables.

As it is, I may bypass the drop-zone feature of drag-select altogether, and just implement my own targeting (drag-over) functionality.

[ThibaultJanBeyer]

Hi @Cyara-Andrew-Watson thanks for this feature request, I believe think this can be added, I'll look into it 👀