WS-179: DataFetcher redesign
WS-179: More-OO DataFetcher redesign: uses classes rather than passing around complex data structures. marshmallow loads JSON locations reports directly into these classes.
"classy" classes have been renamed and pervasive magic strings enumified. database calls are removed, as are hits to archiveService and NGAS in tests.
All command-line options are functional, and retrying failed fetches has been restored.
Edited by Janet Goldstein