docs: Demo ipynb files for plotly,dash,matplotlib

[Jose-Matsuda]

Resolves #30 Documentation in the form of ipynb demos for the following -jupyterlab-plotly -jupyter-dash -jupyter-matplotlib The examples are taken from their respective original docs and are linked to in the ipynb files.

[Jose-Matsuda]

Matplotlib

• added a few extra descriptions in a commit yesterday (I'll add yours as well)

Dash

• The cell does not complete you are right and can run the subsequent commands. I thought it was intended this way (from searching github issues) but there is another issue that makes me think I can make it go away. I'll test it but I think it's switching the order of JupyterDash.infer_jupyter_proxy_config() and

  
  from jupyter_dash.comms import _jupyter_config

_jupyter_config

Scratch above, should be

from jupyter_dash.comms import _send_jupyter_config_comm_request _send_jupyter_config_comm_request()

then `JupyterDash.infer_jupyter_proxy_config()` as pictured [here](https://imgur.com/a/Sb9Xi2r)

A burning question I do have is where do you get the image id `minimal-notebook-cpu:59c4e46f87f41a8649a573e6da20035ac04e3c44` ? 

[Jose-Matsuda]

Uh oh i did something bad out of order