Create a way of accessing SNOMED-CT assessments

[surchs]

We want a source of all IDs and labels of clinical or cognitive assessments from SNOMED-CT so we can use them as our annotation and validation targets.

Options are:

• manually created text files
• SNOMED term server: https://github.com/IHTSDO/snowstorm

TODO

• generate a .json file with the assessments
• put the code either in dev-docs or a repo
• document if we have any hierarchy in these terms

[surchs]

looking at code from #52

[surchs]

Athena Concept ID of "Assessment scales (assessment scale)" is 4157120 from SNOMED

[surchs]

And the terms are unfortunately flat in SNOMED. Also not that many (~2500)