Babylon Viewer Updates

[thomlucc]

Updates planned with the new Babylon Viewer:

• Add shadow support - (PR)
• lazy Load
• XR (incl. WebXR and QuickLook)
• Interaction Hints
• Render Graph support

[ryantrem]

Shadow map shadows were added by #16459 (via shadow-quality="normal"). IBL shadows coming soon.

[ryantrem]

Initial shadow support in the Viewer Configurator was added by #16711.

[ryantrem]

Initial docs added by BabylonJS/Documentation#1372

[ryantrem]

IBL shadows were added by #16696

[ryantrem]

IBL shadows were added to the Viewer Configurator by #16752

[ryantrem]

Support for estimated light position/direction when using IBL + shadow maps was added by #16744