WIP: Rework SIM PIN screen

The SIM pin screen looks out of date and needs a redesign.

IMO it should be aligned with how the lock screen looks. I copied some of the lockscreen code to the SIM pin screen but there are a few things left to be figured out:

The lockscreen darkens the background when showing the numpad. However I was not able to recreate that effect here, so I went with a dark and lightly transparent rectangle instead. Due to the transpareny the content behind is leaking through. The lockscreen does not do that since it paints a wallpaper as background. Should we do the same here? And if so how? Unlike the lockscreen we also have the top and bottom panel visible. I don't think we want that, but I'm not sure how to best get rid of it