[LFS] Implemented screenshot event

[DragonPlayerX]

• Added public accessible EventHandler that provides an event after screenshots are saved. The event contains FilePath, Width, Height and all Metadata values

[knah]

I manually merged this PR in 18f7d8a
Specifically, the patch as-is contains a lot of whitespace/formatting changes that I was unwilling to accept as they're not the important thing here.
Additionally, I've also implemented another version of the API provided here that uses ValueTuple instead, and slightly more user-readable names.