ImageWidget with mixed ndim

[kushalkolar]

This is starting to annoy me in mesmerize-viz, can't have mixed ndim so I made a bunch of sphaghetti to deal with it because I can't just use the new set_data()

Ideas for how to deal with mixed number of dimensions:

1. Last two dims are always the 2D image dimensions, [x, y]
2. We make a slider for every other dim
3. If an image doesn't have a slider for that dim, it's ignored when that slider moves, or if that dim is used in a window function, or apply function etc.

[clewis7]

I think this seems logical, but then for set_data() would we allow setting data with different dims?

[kushalkolar]

I think at this point we should allow that, add a new slider if necessary for a new dim?

[kushalkolar]

I say we officially wait for napari-lite and not implement this in the scope of fastplotlib.