Allow multiple editors per submission

[ahamelers]

Provide solutions for two major issues:

• The original submitter wants to allow someone else to edit their submission (e.g., a grad student graduates and wants the lab PI to control the dataset, or two collaborators want to jointly edit a submission)
• Someone wants to mediate data submission for researchers (e.g., a librarian or data manager)

Original (closed) ticket

Requirements document

See plan to revamp roles into a single table (#1989)

Suggest 3 roles allowed per submission:

1. creator (1 only) the submission's creator
2. collaborator (1 or more) allowed to edit the submission
3. submitter (1 only) allowed to submit for curation/publication; primary contact for the system

Generated in the following steps:

1. The creator is recorded as creator, collaborator, and submitter
2. The creator can add/invite additional colaborators
3. The creator can designate someone else as the submitter (reviewing author)

[ahamelers]

Updated requirements document with outstanding questions for discussion