Expanded animation examples: Scatter3d

[chadamski]

I may be going down a path of unsupported features here, but I have been trying for several days to find/come up with a working example of a Plotly.js animation of a 3D scatterplot. If animations are still unsupported for 3D scatter plots, it might be worth it to mention that somewhere; if they are supported but without tweening, etc, that's also fine, but a clear explanation of what does and doesn't work would be of great benefit to me and at least a few other commenters in the Plotly community forums.