Until now, harvest jobs were set to Finished just after sending all
objects to the fetch stage. Now every time the run command is run, jobs
are set to Running, and all previous Running jobs are checked to see if
all harvest objects have a state of Complete or Error. Only then the job
is flagged as Finished.
`harvest_source_create` and `harvest_source_update` now call
`package_create` and `package_update` respectively, making sure to
define a 'harvest_source' type. The returned dict uses the db_to_form
schema.