change game covers

now we have the ability to change the game logo in the library list, the logo in the gameview and the banner image for the game. being able to change the actual cover would cover everything. the new hydra update also broke games that lack this art causing them to just be slivers in my profile view of my games. hopefully we can get this feature to completely fix this kind of stuff client side at the very least :) also steamgriddb integration would be cool, just so i dont have to download the art on my pc locally and then set them but thats not a need, just a QOL suggestion.