Add basic "View" and "Edit" features to Nuance

Summary:
Ref T8783.

The "View" UI is where a user would check their request for feedback or a resolution, if it's something that makes sense for them to interact with from the web UI.

The "Edit" UI is the manage/admin UI where you'd respond to a request. It's similar to the view UI but will have actions and eventually some queue UI, etc.

(I don't think items need a normal "Edit" UI -- it doesn't make sense to "Edit" a tweet or inbound email -- but maybe this will shuffle around a little eventually.)

Test Plan:
View

Edit

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T8783

Differential Revision: https://secure.phabricator.com/D13980