Cleanup ParaView installations on Windows

• remove <prefix>/lib/paraview-$version/site-packages. That should just move to <prefix>/bin/Lib/site-packages.
• data, doc, etc. stay under <prefix>.
• plugins are currently under <prefix>/bin/. (investigate moving them to a subdir under bin)
• add documentation for what goes where so that we can refer developer to it when adding any new install rules.

SDK notes:

• need to figure out SDK installs.