Add OSPRay Material Editor

This MR adds a new widget named "Material Editor" that builds only when OSPRay is activated and lets a user :

• Load materials with a .json file or Add a new one
• Attach a material to the active source
• Add / Remove / Modify properties of the material

Important modifications :

• A new PVTrivialProducer (proxy name PVTrivialProducerOnAllProcesses) has been added that is created on client|renderserver|dataserver processes
• The Texture proxy is now created on client|renderserver|dataserver (this should be OK as noone uses this proxy)
• Creation of two new widgets : pqVector2DWidget and pqVector3DWidget defined in pqVectorWidget.cxx

A shader ball has also been developed and should come in the next MR

Linked issues #20754 #20749