Purge teratorn from gulo! Update w/latest harvest schema!

Removes teratorn as a dep by moving field definitions into gulo and copying in helper functions and associated tests. Tests are also tweaked to reflect a new source of harvested test data generated using latest tweaks to harvesting schema.

One thing to consider is that if harvesting changes at all, the stats queries won't start to fail unless the test data is updated. Would be really nice to have a test of the full harvesting process.