Transparent Peacock Overlays

Makes the overlays for the peacock web player transparent. The default gradient covers too much of the video. After removing the background manually a few times, I figured I'd make an extension for it instead. Apologies for the screenshot. The peacock web player blacks out any attempt to produce a worthwhile screenshot for copyright purposes I imagine, but the chrome web store requires a screenshot be added. Can't really tell, given the black background, that the overlay is transparent.