Use output profile for the preview pipe

this influences both histogram and navigation image.
(cherry picked from commit 1c2f469de9232a446f5c83849ce49a8040e69608)
camera import: don't compile it by default, it's dangerous.
(cherry picked from commit ea276e40e0e4aa7d77c839aaa629b48e13f12529)
camera import: make it work with/without gphoto2
(cherry picked from commit f522e4be8b7da44d0f3b3ed25bf3626ef857f50b)