enable interactive pyvista examples

Purpose

Enable interactive pyvista plots for 3D examples for improved documentation. Could be useful for ogs docu as well. Since the rendering is done on the client-side interactive plots need to send the model data to the client, thus we should keep model for interactive examples reasonably small. Larger model can still be embedded as static plots in the examples with the corresponding directive.

Application background

Changes taken from a pyvista PR which does the same for their documentation: https://github.com/pyvista/pyvista/pull/4938