Create a nice way of holding environment variables

[mattjbr123]

          Even at a prototype stage I'd start where you want to end up and introduce a config file to hold paths and parameters here. 

omegaconf could be suitable

hydra - saw this recently being adopted by the Minerva project which my old team collaborated on. It's not clear to me how one benefits from both!

Either way, a standard-enough, no-thinking-required way of other people managing their configuration separately from your code :D

Originally posted by @metazool in NERC-CEH#5 (comment)

[dolegi]

https://github.com/NERC-CEH/dri_gridded_data/pull/20/files