Changes

Add mount_to arg to fakespawn command (#2513)

* Add mount_to arg to fakespawn command

* Error if trying to mount_to entity that's not spawned

* PR fixes

* Update max fakespawn command args meta
 (commit: e2e883a)

Initial packet handlers system (#2528)

* Part 1: packet handlers, move to separate classes

* Part 2: `!itworks` TM

* Newline at file end

* Change exception handling

* Only change the bundle packet when needed

* That's a slightly overcomplicated boolean experssion

* Remove `registerPacketHandlerForChildren`
 (commit: e1dd239)

[ci-skip] Fix field naming in a few places
 (commit: 66e8385)

Update player profile packet handler (#2530)

* Step 1: use `ProfileEditorImpl` directly

* Step 2: properly return the modified packet
 (commit: 12919ca)

Cleanup simple packet handlers (#2529)

* Cleanup simple packet handlers

* Simplify fake player packet handler

* Minor actionbar handler cleanup

* Remove legacy `id != -1` check
 (commit: 5e07800)

Update disguise packet handler (#2535)

* Initial cleanup + split

* Cleanup entity getting

* Cleanup general handling

* Cleanup entity data handling

* Cleanup attributes packet handling

* Cleanup reflection usage

* Cleanup disguise sending
 (commit: ab355f0)

Add offthread_repeat arg to relative teleport command (#2533)

* Add offthread_repeat arg to relative teleport command

* Add offthread_yaw/pitch to new teleport offthread_repeat options

* Meta fixes

* Send initial packet then do repeats instead of waiting first
 (commit: 6013532)

Update fake equipment packet handler (#2537)

* Initial method split

* Update equipment packet handling

* Cleanup entity event packet handling

* Cleanup set content packet handling

* Cleanup set slot packet handling

* Cleanup getting the main hand slot

* Make `getMainHandSlot` take a player
 (commit: 1992555)

Add `EntityTag.internal_data` mechanism (#2538)

* Add `EntityTag.internal_data` mechanism

* `setInternalEntityData` -> `modify`

* Add name -> internal ID mapping

* Update meta

* Remove newline

* Fallback to parsing as int
 (commit: 9897530)