Add affiliation filtering

[jukent]

This Issue is 2 parts per discussion in today's EWG meeting:

• Add/check for consistency of affiliation key (Unidata, Project Pythia, etc) to relevant cards in links.yaml
• Update the gallery filtering to look at affiliation keys.

Most of the cards already have an affiliation listed under authors. My goal is to get this information from here instead of duplicating it in another tag.