Add threejs example

[yilinxia]

To ensure that threejs will work

• specify the python package version

  "ipywidgets==8.0.5",
  "jupyterlab-widgets==3.0.5",
  "pythreejs>=2.4.2",
  "ipylab>=1.0.0"

• still the ipylab did not work

[matthewturk]

It looks as though this is also affected by the same thing that was reported here: jtpio/ipylab#129 .