mesh selection sync

[Wunka]

This is just my current progress.
PRs will be made out of this.
First of them is #3648

Goal is to remove all variables in renderer.zig which are for mesh selection, they should either be in the ECS are calculated on the fly, so that at the end, the server can do it too

remaining:

• neighbors (posBeforeBlock and posBeforeBlock)
• lastXYZ (lastSelectedBlockPos, lastPos and lastDir)
• players eye height (is needed to calculate where the player is looking, we should be able to calculate the same value on the server, question is what exactly do we need to use?)