Replace Thebe in Deploy as -> Local dashboard implementation with jupyter-js-* packages

[parente]

Work was started here: jupyter/dashboards#105 and has an open but stale PR here jupyter/dashboards#127.

Bring this work up to date based on the implementation of the frontend JS in dashboards_nodejs_app sans Thebe. Make sure the locally deployed app here remains static HTML for use within the Jupyter Notebook tornado server.

Also, make sure the local dashboards register a session with the Jupyter server so that they can be tracked and cleaned up in the Running tab of the Notebook. See jupyter/dashboards#117 for history.

[parente]

This is on hold while we focus more effort on the dashboard server. The current thebe implementation works fine for the time being. Local deployment within a Jupyter Notebook instance is always going to be a quick and dirty hack given that there's no way to make it secure today. If you give the user a login to your notebook server to view the dashboard, she can twiddle the URL to get to a blank notebook and do whatever she wants.