Loading game/categories from SpeedrunComSharp causes hanging when opening splits

[wooferzfg]

The game and category parse functions are really slow, which could maybe be the cause:

• https://github.com/LiveSplit/SpeedrunComSharp/blob/066d2f0daadfab326f1d51007e56783214354bad/src/SpeedrunComSharp/Games/Game.cs#L72
• https://github.com/LiveSplit/SpeedrunComSharp/blob/066d2f0daadfab326f1d51007e56783214354bad/src/SpeedrunComSharp/Categories/Category.cs#L37

These are accessed in RunMetadata: https://github.com/LiveSplit/LiveSplit/blob/master/src/LiveSplit.Core/Model/RunMetadata.cs

If a splits file has a game name that can't be found on Speedrun.com, or if the API request is cached (which includes caching the parsed object), the splits file loads a couple seconds sooner.