Add nuclear data parsing to Carsus

[andrewfullard]

TARDIS nuclear is in the process of being merged into Carsus. There is a better way of accessing the decay data from NNDC using https://www.nndc.bnl.gov/radlist/, We also have access to the entire dataset of nuclear radiation from https://www.nndc.bnl.gov/ensdfarchivals/.

We should aim to create a unified HDF of nuclear decay data for use in TARDIS.

[chvogl]

@andrewfullard @shreyas3156 I guess this should be finished now?