integrate Cinema volume rendering to work with ParaView GUI and in situ

Integrate the Cinema volume rendering algorithms at !4353 (closed) into ParaView properly. The use case is that users are having difficulties using volume rendering in situ because it is difficult to set up an appropriate opacity transfer function before the simulation is run. We use Cinema techniques to generate a set of opacity transfer functions that can be used in situ to generate images for post hoc exploration of the data. The options for the generating the Cinema parameters are already specified in the MR's server-manager XML file for setting in the GUI and hopefully documented fully there. If the documentation for them needs to be improved, just let me know and I will do that.

The Cinema volume rendering algorithm works as an outer loop beyond existing Cinema operations of camera angle placement but would likely be independent of Cinema operations on contour, clip and slice filters as those filters are unlikely to have volume rendering performed on them.