Qt/trophies: allow to delete a game's trophy directory

[Megamouse]

• Allows to delete a game's trophy directory in the context menu of the trophy manager

fixes #15840

[Augusto7743]

Thanks.

[Jack54guythecoder]

@Megamouse It was a pleasant surprise to see this being actually implemented.
Curious tho, what motivated you to do this?

P.D of something I forgot to add in OG post: A use case scenario can be for example if you want to get rid of a game in a more clean manner, or if you are juggling games a lot (I have all of my games on my laptop`s HDD, so its not easy storing games)

Overall, thank you

[Megamouse]

There was a feature request. That's about it.