Add scripts for beluga_tutorial visualizations

[Alondruck]

Proposed changes

Related to #305, split from #340.

Type of change

• 🐛 Bugfix (change which fixes an issue)
• 🚀 Feature (change which adds functionality)
• 📚 Documentation (change which fixes or extends documentation)

Checklist

Put an x in the boxes that apply. This is simply a reminder of what we will require before merging your code.

• Lint and unit tests (if any) pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
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[Alondruck]

@hidmic @nahueespinosa I don't have much experience with Python, but these two simple scripts represent what we wanted to show. One script automatically advances each time step or simulation cycle (tutorial_animation.py), while the other allows using keyboard arrows to run time backwards and forwards (tutorial.py). These scripts can surely be combined. If you have time, please try it out and share your feedback!

[nahueespinosa]

@Alondruck First pass! I haven't tried it yet, will do shortly.

[Alondruck]

@nahueespinosa @hidmic The propagate and reweight stages actually represent the same graph, as both are histograms of the same distribution of the set of particles. Do we need to show the reweight stage in a different way, or is it sufficient for what we expect from the tutorial?

[nahueespinosa]

Do we need to show the reweight stage in a different way, or is it sufficient for what we expect from the tutorial?

If we opt for the histogram display, then I think it makes more sense to show only three stages: current, prediction (currently called propagation), and update (reweight + resample). This would match the description on the key concepts page about the two main stages in a particle filter algorithm: prediction and update.

[nahueespinosa]

LGTM