Restrict submissions to the entity actions listed in the form

[matthew-white]

I have an entity list and a form whose submissions create entities in the entity list. My workflow is fairly controlled: submissions create entities only after approval, and I don't use submissions to update entities. Within this context, submissions will specify a create attribute on the meta/entity field. If the submission XML is manually modified to specify an update attribute, then the submission should be rejected. That is, the only action attributes allowed on meta/entity in the submission XML should be those specified in the form XML.

I think this will be especially important once we support entity archiving. You could imagine a public link form that is allowed to create entities, but that definitely shouldn't archive entities.

[ktuite]

This would involve parsing the create/update attributes when we read the dataset definition, saving those actions in the database (in a way that is linked to the form def, so different versions of a form can do different actions), and checking those as submission-processing time.