Renaming `ThreadedAnvilChunkStorage`

[Leo40Git]

I have 2 problems with TACS' current name:

1. Anvil - this class does not deal with the Anvil chunk format at all! That's handled by ChunkSerializer.
2. Storage - this class is actually a chunk manager, not just storage!

Additionally, there's the field that stores an instance of TACS in ServerChunkManager. You'll never guess what it's called... and ServerChunkManager delegates most of its actions to this instance (see my 2nd point)!

Therefore, I propose:

• We rename ThreadedAnvilChunkStorage to ThreadedChunkManager.
• We also rename ServerChunkManager.threadedAnvilChunkStorage to ServerChunkManager.delegate.

[ix0rai]

is there any reason no one has ever made another pr for this change?

[Leo40Git]

beyond me being too lazy, no