Extend plot support for entanglementplot and transferplot to Makie.jl

[borisdevos]

Deals with #249. This works locally, below I attach the results for both Plots.jl and CairoMakie.jl*. I didn't really test any other Makie backend, but I think CairoMakie is the one you want anyways in this context.

As you can see in the attachment, I didn't really bother to make the Plots.jl plots any prettier than they were, and they remain equally blurry. Anyone willing to prettify these, feel free to do so. I put slightly more effort in the Makie plots, but even there plenty of improvements can be added.

I added todo's here and there, mostly stylistic choices.

*There are two plots per function, just to show that keyword arguments are being taken correctly:

# gs is the ground-state of the Ising Hamiltonian at g = 0.1
entanglementplot(gs)
entanglementplot(gs, expand_symmetry = true, sortby = maximum, sector_formatter = c -> "Sector $c")

transferplot(gs)
transferplot(gs; sectors = [Z2Irrep(0), Z2Irrep(1)], transferkwargs = (; num_vals = 1))

someplots.pdf

[lkdvos]

This definitely looks great!
I have a couple questions, mostly since it has been a while since I looked at Makie:

Do you know if the other attributes can still be set/changed? For example, what happens if I want to override the default title/ticks/...?

I seem to recall also that there was some system with observables etc, where various parts where dynamically recalculated. Do you know if this is still relevant?

[lkdvos]

This should probably be a weakdep?

[lkdvos]

Does this make sense to have as a default dependency? We could in principle also have a default xlabel that uses Unicode, and require people that wish Latex strings to specify the xlabel themselves (which I would assume people typically want anyways)

[borisdevos]

At least for Makie I could keep the default latexstring expressions and put it as a weakdep, since it's explicitly in the deps of Makie. I put it here in deps to get it working for Plots, but we can indeed default to whatever and let the user overwrite themselves (if possible for Plots, I think I've got it working for Makie right now)

[borisdevos]

I just tried some random keyword arguments for the Makie plots, and they seem to work. I'll test tomorrow if I can do the same for Plots.
(Also I realised I was running Z2-symmetric MPS in the Z2 SSB phase 🫠)