Resource gets added to RSS on PUBLIC, not on published #1248

Steps:

1. I add a new resource to our IPT
2. The to-be-published version 1.0 of the resource will be public, so I set visibility to PUBLIC. Since I haven't finished writing the metadata or uploading the data yet, I'm not yet publishing the dataset.
3. The status PUBLIC triggers the IPT to include the resource in the RSS.
4. Via IFTTT a tweet is sent with the link to the not-yet-published dataset.
5. Visitors of the link see an Not authorized page

Solution: Setting a dataset to PUBLIC should not trigger the IPT to update the RSS. Only publishing a resource should trigger this.

Note: the not-yet-published resource is NOT included in the DCAT feed, which is the correct behaviour.