Installed / Not-installed badge

[Former user]

This is a simple idea but one that would greatly help people with large collections of steam games, simply add a checkbox in the game options to mark as "installed", then show a badge (like a green "check" mark or something, or a play icon) for installed games, otherwise show a grey badge of a download icon (for example), then we could filter games by that status, the badge should be visible overlaying the current game icon (logo, box, steam banner etc) if the user wants to.