Datasets (Package) should have owners

[ross]

Each dataset should have an explicit owner that is an organisation. This is the organisation that owns the dataset* and will be used for specifying who can move a dataset out of the default organisation.

This should probably be a foreign key link from dataset to organisation (or rather group).

• Currently this won't necessarily be the organisation that the dataset is a member of, but it is likely that this will be the case initially (at least until someone moves it to another organisation).

[seanh]

Closing as we've moved forward with a slightly different approach to organizations in core instead.