Add a widget for displaying statuses

It can display either primitives or saved statuses.

Then use the widget in the status manager and the status editor.

Testing Done:
Edited a status, and confirmed that the list of status primitives were all shown
Opened the status manager, and confirmed that the saved status' primitive in the manager changed as expected after editing the status.

Reviewed at https://reviews.imfreedom.org/r/2417/