Sort RefBy fields logically

[samm82]

As noted in #3259 (see this comment), the output FR shows up first in the list in the RefBy field (the following screenshot is from IM:calOfLandingTime from the Drasil website):

I would think that the IMs would be first, then the FRs in the order they appear; the order of these should follow some logic. Maybe the ordering of the columns/rows in the traceability matrices (or the order they appear in the document, if different) could be used as a reference for how to sort them?

[balacij]

Yep, it's just sorted by UID right now if I remember correctly. I think @JacquesCarette suggest sorting by visible label in #2468.

Now that I see it, the labelling/abbreviation convention doesn't seem uniform. IM labels follow camelCase while the (N)FRs use Upper-Kebab-Case.