Make sure people using the communities list know they have an official unaltered version

[katherinedm-usds]

Is your feature request related to a problem? Please describe. When groups working on the same project are sharing a communities list .xlsx or .csv, it might happen that people start using for their analysis .xlsx or .csv files that have been modified.

Describe the solution you'd like When people share CEJST information about communities or cite the CEJST data, we should communicate to them that they have an official unaltered version of the CEJST data. One simple solution to implement as @esfoobar-usds suggested would be to make a checksum of the file available on the CEJST.

We can wait on implementing this until at least the next major methodology update, or more generally when a visitor to the site flags this as an actual real problem.

Describe alternatives you've considered

Additional context