feat: implement draco decoder

[okwasniewski]

Summary

This PR implements DracoDecoderModule API.

It's following the spec from upstream google/draco.

// Create the Draco decoder.
const decoderModule = DracoDecoderModule();
const buffer = new decoderModule.DecoderBuffer();
buffer.Init(byteArray, byteArray.length);

// Create a buffer to hold the encoded data.
const decoder = new decoderModule.Decoder();
const geometryType = decoder.GetEncodedGeometryType(buffer);

// Decode the encoded geometry.
let outputGeometry;
let status;
if (geometryType == decoderModule.TRIANGULAR_MESH) {
  outputGeometry = new decoderModule.Mesh();
  status = decoder.DecodeBufferToMesh(buffer, outputGeometry);
} else {
  outputGeometry = new decoderModule.PointCloud();
  status = decoder.DecodeBufferToPointCloud(buffer, outputGeometry);
}

// You must explicitly delete objects created from the DracoDecoderModule
// or Decoder.
decoderModule.destroy(outputGeometry);
decoderModule.destroy(decoder);

Test plan

Test if decoding .drc files work properly.

[mani3xis]

I found some remarks in the first reading pass.
I'll check the remaining code later when I'll find a time slot.

[fvlvte]

LGTM!