Utility method/mock for setting up a test data directory

• Reusable method/mock for data directory in tests
• Double check data directory documentation
  • data/FIREID/
    • debrisflow/
      • shape file(s)
      • thresholds file
    • stations.csv (lat/lon/id/last updated/etc)
    • stations/STATION.csv
• set up test data directory
  • tests/data/mesowest
    • JSON data file(s)
    • JSON station file(s)
  • tests/data/fires/tun2022
• update existing config/datastore tests and remove vcr/cassettes (move to tests/flowalert from tests/src/flowalert)