Feature request: allow package document owners to set permissions on who can submit package documents to EDI curators

[gkamener]

This is a request to consider adding a feature that would allow ezEML package document owners to restrict collaborators from submitting the document to EDI curators through ezEML. This would be helpful in cases where the document owner should be the person to submit a finalized document to EDI curators. This would also help LTER sites prevent package collaborators from accidentally submitting to EDI curators in cases where the LTER site's account is the document owner. Ultimately, document owners are responsible for communicating any specific submission expectations to collaborators in such cases, but this proposed feature would be helpful in enforcing those expectations.