Improve notebook support

[fdxmw]

The wavedrom trace visualizations don't work reliably across different notebook platforms (Jupyter Notebook, JupyterLite, Google CoLab, MyBinder, ...)

The notebook examples are currently out of sync with the main examples. Look for ways to keep them automatically synchronized so we don't have to keep re-syncing them. See also #376

Migrate the notebook examples on https://ucsbarchlab.github.io/PyRTL/ from MyBinder to JupyterLite, so the examples run entirely in the browser, and don't depend on a server.

Experiment with interactive notebook visualizations. It would be really cool to pan/zoom/filter a trace visualization.