Add persisted state
Add persisted state

Summary: Persist state in Mobile builds plugin. This diff also moves the logic of percentage updates in the persisted state.

Reviewed By: mweststrate

Differential Revision: D21840853

fbshipit-source-id: 3246cdfecfca12cd0f269f5a87646cf619380999

facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper