ParaView plugin fixes

A smorgasboard of fixes + improvements to ParaView support.

These changes have all been squashed down into 1 commit so it will be easier for TJ to rebase the operator branch:

• Fix the conversion of phrase path to QModelIndex. Phrase indices/paths should be ordered top-to-bottom; the index of a descriptive phrase goes from top to bottom as the index is traversed from beginning to end.
• Improve phrase-list handling. Now manually-specified subphrases are properly handled by setting the phrase content to a phrase list that has a properly-generated default title.
• Set active pipeline source from panel. When a resource is selected in the panel, make its pipeline source active. If multiple sources are selected, make the first we encounter active. This allows CMB v6 to do without the pipeline inspector while still providing a way to set each resource's color-by mode and other display properties individually.
• Prevent a crash on exit. The pqSMTKResourceManager was being destroyed after its server but with no signal that the server was going away. This caused the resource to ask for a pointer to a partially-destroyed resource manager during its destruction.
• Always clear the PV cache-keeper when the model changes. Otherwise, the representation geometry can be stale when the filename is changed by the user.
• Remove a debug printout of a JSON-RPC response.
• Add an SMTK model for testing. This is just the pmdc model but with edges and vertices created as needed. It also has color set on some (but not all) volumes so that color-by-volume mode can be tested.
• Address TJ's comments on the MR.
• Add a "color-by" toolbar for the model representation. The pqSMTKColorByWidget class draws heavily from ParaView's pqDisplayRepresentationWidget and the pqSMTKColorByBehavior class similarly from pqRepresentationToolbar.
• Fix dashboard warnings.