Use `daft` to display graphical models in examples

[The hierarchical BBN example](https://blackjax-devs.github.io/blackjax/examples/HierarchicalBNN.html) has embedded pictures in the notebook. We should use the [daft library](https://docs.daft-pgm.org/en/latest/) to render the models in this example, and also in other examples instead.

Start with the hierarchical BBN example linked in the issue and inspect the notebook behind HierarchicalBNN.html, then review the other examples that contain embedded model pictures. Use the daft documentation to determine the rendering approach; done means the relevant examples render their graphical models with daft instead of embedded pictures.

Written by the indexing model from the issue text.