Clean up paraview.org with regards to ParaView Guide

In the paraview.org website, when you go Resources/ ParaView guide, you get to https://www.paraview.org/paraview-guide/. In this day of online documentation, please have this page go directly to the online ParaView guide, located here: https://docs.paraview.org/en/latest/. Further, let's get rid of the paper book version of the ParaView Guide. The current one is ParaView 4.3. If no one has complained in the last half decade, no one is reading it.