This slightly refactors the name generation in outputlocator to ensure
we don't add spaces when there's nothing to add a space to. It also
ensures that if we can't determine a proper name because all parts are
empty we return "Unknown" as name.
An effect that implements the "identify" functionality of
the screen configuration kcm. It displays a label on each
screen that identifies the screen.
Doing this as a kwin effect allows to correctly handle
the case when outputs are mirrored (on wayland) compared to
absolute positioning of windows which end up on top of each other.
