prep page for desgin work
This commit not only restores the AttachmentsController, but also creates CollectionsController and AdminPoliciesController -- all three for :new and :create actions.  ObjectsController won't be used for creating new objects -- i.e., hydra-editor will only be used for edit/update of descriptive metadata.
Merge pull request #681 from duke-libraries/restore-attachments-controller

This commit not only restores the AttachmentsController, but also create...
Merge branch 'develop' into 292-upload-content [ci skip]