Add WM_ROLE to windows generated by flameshot

[yggdr]

Feature Description

Currently I cannot easily control which of the windows flameshot opens (like configuration, or the "Pin to desktop"-window) should be set to floating in my i3 configuration. With firefox e.g. I able to filter for window_role="PictureInPicture" to have the video player popup automatically in floating mode. In flameshot, I can only really filter for the entire class='flameshot'. Adding WM_ROLE to the various windows opened would make this selection more granular.