Auxiliary data for RetrievalToolbox.jl EM27/SUN demo application

This additional data is needed to run the EM27/SUN retrieval demo (https://github.com/RetrievalToolbox/EM27-retrieval) that is implemented with the RetrievalToolbox.jl software library. This repository contains (1) spectroscopic tables that were generated with the ABSCO toolset (https://github.com/ReFRACtor/ABSCO) which itself uses line parameters from the HITRAN catalogue (2) example EM27/SUN measurements (as pre-processed with the PROFFAST software), model atmosphere priors (as produced by the GINPUT toolset)