Proposal: create the concept of "Dataset" which can be rendered in different ways

[stellasia]

Is your feature request related to a problem? Please describe.
Closely related to the problem of duplicating an existing layer (#83). Right now, if you want to have two different renderings for the same data configuration, you have to create twice the same configuration, and repeat all changes between the two layers.

Describe the solution you'd like
It would be great to be able to define a dataset (a data configuration), that could then be rendered many times, available rendering options depending on the "columns" in the dataset.
This would also let us fetch the data only once.

Describe alternatives you've considered
The alternative of duplicating an existing layer does not solve the issue of copy/pasting the changes if one layer is modified. But the two approaches are not mutually exclusive, we can have both.

Additional context/open questions

• Do we need distinct node/relationship datasets?
• Need to do some research for the UI, that would be quite different (use tabs? hide map during dataset configuration?)