Add "panic behaviour"

[MrElliwood]

Implementing a panic responder as laid out here https://guardianproject.info/ar/code/panickit/ seems like a great addition to all Apps. Here are a few ideas of what a panic event could trigger:
Once a panic event is triggered all, or selected apps could hide themselves.
The file manager could have a list of files and folders to delete on a panic event.
The gallery could show "dummy pictures" instead of all folders.
The Notes app could hide all notes until a new note with a specific title set in the settings is created.