[feat] Physics(FakeTee) entity

[TsFreddie]

These are not custom entities, if a modder wants a custom physics objects they should code it or use something like box2D.

But we should provide a entity based on existing teeworlds physics (CharacterCore). So:

• a gamemode like ball-kind of game can use the physics entity behave like a dumb throwable tee/object.
• a monster kind of gamemode can use it as bots.

all without taking up any client slot (preferablly with configuarble size).

Maybe related to #13