Add an example of integration with Blackjax?

[rlouf]

I think Oryx and Blackjax are very good match, would you consider adding an example of using Oryx as a modelling language to generate a logprob that Blackjax can use?

[sharadmv]

I think the example here might be a cool one to port to BlackJax inference. Unfortunately I probably won't get around to it for a while but contributions are welcome!!