Render Plotly graphs in Sphinx documentation

[tpvasconcelos]

Currently the Sphinx docs (https://ridgeplot.readthedocs.io/) do not render live plotly graphs. Instead, they contain static screenshots for all available examples.

We could make use of Sphinx-Gallery to help us use real Plotly graphs. See this example from their docs.

[tpvasconcelos]

This has already been addressed (without using sphinx-gallery)