Add CMake option FILAMENT_USE_MULTIVIEW_STEREO

[z3moon]

Passing -DFILAMENT_USE_MULTIVIEW_STEREO allows the generated project files to contain the preprocessor FILAMENT_USE_MULTIVIEW_STEREO. This will be referenced to determine which implementation for stereo rendering should be used at compile time.

The value of this parameter defaults to NO, which sticks to the original behavior.

[github-actions[bot]]

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