Replace precomputed rates in HDF5 file with those from CHIANTI via fiasco

[wtbarnes]

The recombination rates are currently stored in a (version-controlled) HDF5 file. If it is more ideal to not have to maintain this relatively large chunk of data, I will note that fiasco, while still in early development, can calculate relatively easily the ionization and recombination rates as a function of temperature from CHIANTI, e.g. https://fiasco.readthedocs.io/en/latest/generated/gallery/plot_recomb_rate.html.

In can also calculate the equilibrium populations as a function of temperature which is likely useful for constructing a set of initial conditions, e.g. https://fiasco.readthedocs.io/en/latest/generated/gallery/plot_ioneq.html#sphx-glr-generated-gallery-plot-ioneq-py. It looks like this is already done here though:

PlasmaPy-NEI/plasmapy_nei/eigen/eigenclass.py

Line 24 in 7c6700a

def _get_equilibrium_charge_states(ioniz_rate, recomb_rate, natom):

It might be worth comparing these two approaches

I realize that having a dependence on an unreleased package is not ideal. I would be happy to push to cut a release of fiasco if having this dependence/capability is something people want.

There is probably also some work to do to reconcile the different ways fiasco and plasmapy treat ions/particles.