Argo fix

Big update on the harvester to fix a few issues, and to fit the way harvesters are currently being written.
Can be merged and run on RC first. 

This harvester ran OK on my vagrant machine after running the version currently on Prod, so it should run ok.

The harvest type position is now "POSITION" to match all the other harvestType cases (all uper case). Which means that all file_id's with the 'harvest_type' column from the 'file_harvest' table will have to be deleted with cascade. I didn't do it in the liquibase because I thought this would be not a really clean way to do.