Merge similar games into one
We had a game duplication problem that has been fixed by dropping new instances of the game (!61 (merged)).
Instead of ditching the new instance out, we should tryg to merge it into the existing one. For example for retro-based platforms it means merging the medias, each media can have multiple URIs so that if a UIR happen to not work, we could try using another one (e.g. one is a cue sheet coming from the Flatpak portal and doesn't work because the files it list can't be found but the other one comes from Tracker and the files it lists are its sibblings).