Camrea2: overlays continuous focus/Cancel autofocus if preview stopped

Change-Id: Ie3958f5bea781dcac2be373b43aca791a36ddd4d
Revert "d2-common: remove continuous-picture mode"

This reverts commit 4b8f6c7709f64b09733bda018cd33b121a5c0e4b.

Change-Id: I9401c2de913ab8ba9b3992894c6ae5d8f9d166bb