Spack: Add ability to only build new catalyst/conduit library
@utkarsh.ayachit @cory.quammen @patchett2002 Let me know if this is reasonable or not.
It would be great if we could build the standalone Catalyst library in Spack (either in a separate package or as part of the current paraview package). I'm setting the milestone to 5.10, and I'd be happy to work on this myself.