Project: Allow sorting of users on detail page

[dsajdak]

On the project detail page, we have sorting for allocations, publications, and grants. We should be able to sort by username, email address, users' first and last name, and role. The user first and last name is currently displayed as one entry so may need to be separated out to allow proper sorting.

[dsajdak]

The break up of full name to first and last is done on the 'remove users' page so this should be very easy to sort there, as well as on the project detail page