2044: All users can give all other users folder permissions.

This supports a Workbench sharing button, the same way that the
changes to users#index does.
2044: API server lets group managers see group permission links.

This implementation hooks into find_object_by_uuid because that was
the simplest thing that could work and unblock larger development on
this story.  Longer-term, we would like to solve this problem more
generally.  See the comments added to the links controller test for
more explanation about that.
2044: Workbench supports API select parameter.

This can help ensure symmetry between admin and non-admin requests for
the user index.
2044: Add more helpers to get FA icons for objects.
2044: Workbench can query the API /permissions method.
2044: Workbench route to share a project with others.

This route is intended to support AJAX requests from the interface to
share a project with one or more users/groups.
2044: Add Workbench interface to manage project sharing.

This empowers administrators to add, modify, and remove permission
links on projects.
Merge branch '2044-workbench-project-sharing'

Closes #2044, #2749, #3238.