add harvest_object_create action
[#65] harvest_object_create action

update to use schema and validators. Also accept more parameters to
data_dict.
[#65] remove unused code
[#65] make harvest_job_exists validator return model object

return the model in the validator instead of checking that it exists in
the validator, returning the id and then fetching it again in the action
function
Fixed typo: ampq -> amqp