Collaborators should be able to add notes, but not change anything else in MIQA

[jeffbaumes]

As a workaround, we have left collaborators with read only access and we just don't show them and "edit" type widgets in the UI, because none of those would work for them. Fixing this in the long run seems like it will involve at the least reorganizing how metadata is stored (currently notes and ratings are both part of generic metadata attached to the scan folder), but might be even more challenging given how Girder groups work in version 3.