disguise api

[yannicklamprecht]

relates to #10584

Adds a simple disguise api that also makes sure that invalid entity data, not belonging to the type that is faked, is filtered.
It also adds a server generator module to reduce maintenance of the entity data filter.

tldr; The API provides a way to disguise any entity as another or a player with having the possibility to interact with the entity like with any others. The big advantage is that you've the whole vanilla logic and Mob Goal and Pathfinding included without hassle.

Testing the changes can be done using the following snippet:
https://gist.github.com/yannicklamprecht/639acba127a54f5617e1281f099b7aff

TODO:

• Add JavaDoc
• remove test plugin code
• comment paper-server-generator
• figure out how to get teams working with real teams, client side ones worked in my fork Non issue just use the Entity#getName() instead of the Entity#getScoreboardEntryName()
• remove player profile if player disguise on ServerEntiry#removePairing(player) to avoid client disconnects when moving away and approaching again. see disguise api #10478 (comment)
• wait until dev/1.21 is merged into master
• When player is disguised as entity his attributes are propagated to the client, which isn't supported by certain entities
• When player is disguised as entity that has no ability to interact/build, the server should not propagate the players action to the rest of the players. Otherwise the other player gets kicked.
• When changing disguise while in visible range from e.g. Boat to a Living entity disguise, attributes will be sent again. -> on disguise change => auto hide and show entity to players.

Effective loc:

• 600 loc in patches
• 3k+ loc generated filter classe
• 400 loc generator code copied from api-generator
• 100 loc for generating the filter class.

[XxGoldenbluexX]

good job!