Issues with airports dataset

The current version uses a fixed list of airports from https://ourairports.com/data/, filtering them by `type` (only `medium_airport`s and `large_airport`s). The filtered list is stored here to avoid downloading a large file with heliports: https://github.com/nerik/airports-streamlined

Before considering using real routes, we could improve the existing structure:
- update the airports file to the latest version. See if it fixes SJC and FSD missing
- (better: submit the filtered versions to the [original repo](https://github.com/davidmegginson/ourairports-data) ?)
- use `medium_airport`s and `large_airport`s to get closest airport to team member, __but only use `large_airport`s for candidate meeting locations__

Thoughts @kamicut ?