Update handling of anisotropic material properties for engine v2.8

[mvaligursky]

The v2.8 deprecated anisotropy property, and added anisotropyIntensity and anisotropyRotation.
Also anisotropyMap has been added.

What needs to be done:

• anisotropy needs to be migrated to anisotropyIntensity and anisotropyRotation (while leaving the original property for older engines)
• anisotropyIntensity and anisotropyRotation exposed in the inspector for new engine
• anisotropy hidden for the new engine
• exposed new map in the inspector for the new engine

related PRs
playcanvas/engine#7668
playcanvas/engine#7708