Beatmap V4 support

[Fernthedev]

To be clear, I'm not trying to push for a rush to support a new format that no one really needs or wants. I don't think V4 should be considered for CJD at all for a long time given that it's a major paradigm shift to what we're used to working. However, I want to make this issue to track along ideas on how we would support V4 (if at all) for both PC and Quest (given that PC is in limbo and Quest is closing in on 1.35 very soon)

Here's some ideas I have, though not exclusively should be considered:

• Since the data arrays where object data is stored are now value types, no inheritance + field additions can be considered. However, BeatmapBeatIndex is not a value type
  • We can add customData there as a field
  • Add a field that does a lookup to a table, similar to the colorNotes | colorNoteData array setup. I don't think this is useful since it causes overhead and V4 supports gzip unzipping which does more or less the same thing.
• Not support v4 at all, leave it as is

There's other things to consider, such as v2 light event support (since lightshow data is now separately in a file)

P.S I'm not well versed with the new Beatmap Loader framework they built so I might be overthinking or naive with the ideas I mentioned.