Add WIP pyvista 3d guide

[jbusecke]

I have been working a bunch of 3d visualizations and I would like to push this into a more useable feature for LEAP-Pangeo users.

• I think we should add a guide to remake my rotating earth work (I collected the code here).
• Ultimately this should be faster on the hub by actually using a GPU! But this might require some more deep work.
  cc @auraoupa who expressed interest in this.