Add naive sensor fusion support

[hidmic]

Feature description

In general, the more information you have, the better your estimate will be. Alas, our bootstrap particle filter (BPF) workhorse can only reweight particles with one sensor model. We need mechanisms to aggregate multiple measurements, to perform sensor fusion. There are many such mechanisms depending on how you model your estimation problem, but I think we can cover quite some ground just assuming conditional independency and multiplying 👀 sensor model likelihoods.

Implementation considerations

Unclear as to whether this should a sensor model aggregate or a new reweight action 🤔. I'm slightly inclined towards the latter.