Save grid rotation to beatmap

[kstefanowicz]

Adds the GridLinesRotation int from OsuGridToolboxGroup.cs to the [Editor] portion of the beatmap .osu file. Allows grid rotation to be saved instead of reverting to default every time the map is loaded.

I'd imagine something similar can be done for StartPosition and GridType, but I am not familiar enough with C# typing to implement.

Osu-Save-Rotation.webm

[frenzibyte]

See #28473, #23418, #28810, #20883. The grid rotation should be part of the .osu file, not in the databased model.

[kstefanowicz]

This implementation does add the grid rotation to the .osu file via LegacyBeatmapDecoder.cs and reads it via LegacyBeatmapEncoder.cs

[frenzibyte]

Yes but it's also persisting it in the database by adding it in BeatmapInfo, which is frowned upon. It should be added in IBeatmap (which is what I mean by .osu file). I've closed this PR until the concern in #20883 is resolved first.

[peppy]

@OliBomby you were tackling this last i heard, including more than just rotation. do you have anything to show yet?

[OliBomby]

@OliBomby you were tackling this last i heard, including more than just rotation. do you have anything to show yet?

I had created a working implementation by adding the properties to BeatmapInfo but didnt create a PR because we dont want it it in BeatmapInfo. I'm waiting on the PR that moves stuff out of BeatmapInfo #28473