block: add NGLI_TYPE_MAT3 support
block: add NGLI_TYPE_MAT3 support

This will be used internally by the upcoming Vulkan backend to copy 3x3
matrices (used for normal transformations) to UBOs/SSBOs.

gopro/gopro-lib-node.gl,gopro/gopro-lib-node.gl,gopro/gopro-lib-node.gl,gopro/gopro-lib-node.gl