chore(exampleNotebookMenu): move example notebooks to directly under file menu
chore(exampleNotebookMenu): move example notebooks to directly under file menu

0u812/nteract,rgbkrk/nteract,nteract/nteract,0u812/nteract,rgbkrk/nteract,nteract/nteract,nteract/composition,jdfreder/nteract,captainsafia/nteract,jdfreder/nteract,jdetle/nteract,jdetle/nteract,temogen/nteract,jdfreder/nteract,temogen/nteract,rgbkrk/nteract,jdfreder/nteract,captainsafia/nteract,nteract/composition,rgbkrk/nteract,nteract/nteract,captainsafia/nteract,temogen/nteract,jdetle/nteract,nteract/nteract,captainsafia/nteract,0u812/nteract,jdetle/nteract,0u812/nteract,rgbkrk/nteract,nteract/nteract,nteract/composition