feat: allow setting the camera position

[gabotechs]

As requested by #44.

This would work as follows:

function Component() {
  const cameraRef = useRef<CameraRef>();

  function setCameraPosition() {
    cameraRef.current?.setCameraPosition({
      latitude: Math.PI / 8,
      longitude: -Math.PI / 8,
      distance: 1,
    });
  }
  
  return <StlViewer 
    cameraProps={{ ref: cameraRef }}
  />
}

A more detailed example can be found here https://github.com/gabotechs/react-stl-viewer/blob/master/.storybook/stories/FromUrl.stories.tsx