refactor(shapeshift): use yOffset instead of temporary render offsets

[hinyb]

This is a refactored implementation following the suggestion from @Alexdoru in GTNewHorizons/Hodgepodge#802
I chose to modify RenderEntityViewer instead of PlayerRender, as PlayerRender is too complex and contains many unrelated logics. This still fix waila's tooltip issue.

[Alexdoru]

Inject in the PlayerRender class and cancel all the code after EntitySizeInfo size = new EntitySizeInfo(player); and in your entityRenderer mixins just copy the code that computes the offest

[Alexdoru]

and remove the RenderEntityViewer mixin

[Alexdoru]

I found an issue with the resizing potion which is unrelated to your PR : if you go in a 1 block tall hole while you are resized, you will suffocate because it checks for the "normal" head position which is inside a block, something to fix in another PR if you want.

[Alexdoru]

There is a major issue, if you quit your singleplayer world while shpe shifted when you try to rejoin you get automatically kicked for illegla stance

[hinyb]

There is a major issue, if you quit your singleplayer world while shpe shifted when you try to rejoin you get automatically kicked for illegla stance

Sorry for the late response. I forget to sync the OffsetContents. Fixed.

[hinyb]

I found an issue with the resizing potion which is unrelated to your PR : if you go in a 1 block tall hole while you are resized, you will suffocate because it checks for the "normal" head position which is inside a block, something to fix in another PR if you want.

It is actually caused by the resizing potion incorrectly setting the eyeoffset on the server side. Since it is also a type of shapeshift, I decided to include the fix in this PR as well.