Publisher support for harvesting

[amercader]

Estimate: 4-5d

Only sysadmins can manage harvest sources right now, we need to allow publishers to handle their own sources.

We need to decide if there will be two different profiles on ckanext-harvest, the current one with only sysadmins allowed to manage the harvesting and a new one supporting publishers (ckan core can be configured to not use the publisher model)

Tasks include:

• Auth checks on the different controller actions (and the command line interface?)
• Modify the index page to just show sources the logged user has permissions on.

(Talk with Ross about the specific functions to use)

• Create/edit form to show a dropdown with the user available publishers.