[Savestates] Fixed world being unloaded after loadstate

[ScribbleTAS]

This has been a thorn in my eye for a while... The chunks are rarely loaded when you load a savestate... If they are not, the motion of the client is also reset...

I've been dancing around this issue for a while and I think I got it down, finally...

The issue was that

1. The chunks, after being loaded, where marked as "ticked = false". So when it came to sending the chunks, a check would prevent that.
2. The chunks were not sorted(?) before sending them. Chunks are sorted every 4 ticks and savestating will also prevent that

Changes

• Added new MixinPlayerChunkMap and PlayerChunkMapDuck to add new methods to the chunk map
• Removed AccessorPlayerChunkmap, as it's handled via ducks
• Removed MixinWorldServer and WorldServerDuck as it's merged with the chunkmap duck
• Updated some documentation

[ScribbleTAS]

Note that github actions are currently biting the dust, so builds may take a little longer to appear https://www.githubstatus.com/