Interactive plot issue

[YooSunYoung]

plotly backend works easily in all candidate visualization frameworks but matplotlib doesn't.
We might have problems using 3-D instrument view in the dashboard if matplotlib is not available.
We might want a standalone interactive plotting module in the plopp. Still need to discuss about.

Related to scipp/plopp#150

[nvaytet]

We might have problems using 3-D instrument view in the dashboard if matplotlib is not available.

Note that the 3D plots do not rely on matplotlib, but on pythreejs which itself relies on ipywidgets. So the issue would not be to get matplotlib to work, but ipywidgets.
That said, interactive matplotlib figures also seem to need ipywidgets because they use the ipympl backend which uses ipywidgets.