Add very basic create interface for Pholio

Summary:
Nothing app-specific yet, just stitching groundwork together from readymade components.

{F22347}

Test Plan: Created some mocks via web UI.

Reviewers: btrahan, chad

Reviewed By: chad

CC: aran

Maniphest Tasks: T2097

Differential Revision: https://secure.phabricator.com/D3830