R1:515f9a36ab7a

When editing objects which use files, attach the files to the objects

Summary: Ref T603. Fixes T3921. Tightens up policy controls for file/object relationships in existing applications.

Test Plan:
- Uploaded new project image, verified it got an edge to the project.
- Uploaded new profile image, verified it got an edge to me.
- Uploaded new macro image, verified it got an edge to the macro.
- Uploaded new paste via web UI and conduit, verified it got attached.
- Replaced, added images to a mock…