Synchronize upstream with ETL Updates
Created by: slifty
This PR consolidates the GPG decryption logic into a single location and updates the modern competitions to use the centralized logic instead of the duplicated logic.
It also pushes two ETL changes:
- Tabs on LLIIA2020
- Decryption of finalist zips for LLIIA2020
It does NOT yet process the content of the finalist zips in 2020, since the local implementation included references to applicant names and needs to be given the finalist-csv treatment to keep secrets secret.