Feature Request: add Lingering effect on FaceDetect plugin marker

[BaconCondensate]

Pixelate/Blur effects has a problem detecting faces sometimes, especially during a decently fast movement, a toggle-able lingering blur effect on detection loss would be nice to obscure the problem

[samozrejme]

or a toggle of the default state to make it basically "fail-secure" ☑ Blur whole screen if face is lost.