Explore using Pixi environment with source Parcels installation for Binder

[VeckoTheGecko]

As the title says. To be done post release of Parcels v4 (hence is blocked for now)

---

Background:

Ah yes.... We can add Pixi support in our Binder setup, but that actually wouldn't really help since we're still installing Parcels from source.

We can only use released versions of Parcels @reint-fischer . You can either:

• Update the binder to be along the lines of https://github.com/Parcels-code/10year-anniversary-session4/blob/main/environment.yml - installing from our alpha channel
• (I recommend) Don't worry about binder on v4 for now and just work using the environments we have. Down the line we can look at getting the Binder working so that it pulls from the test-notebooks environment (which I think would be best)

Originally posted by @VeckoTheGecko in #2318