Clean up, do TODO, fix TOFIX

[vatro]

Clean up + do TODO / fix TOFIX only issues things that cannot be moved to 1.0.0-next.X. If something cannot be resolved within an hour, create a new issue for 1.0.0-next.X, we want to get 1.0.0-next.1 out asap.

• Close Determine lowest supported three version #11
• Close Clean up / refactor add_instance_to() logic + related #71
• Try to close Figure out hot to handle shadow_root and shadow_dom_target in non-svelthree 'container' components #72
• Close Propeller.ts : check / remove confusing, old, camera.view related comment  #77
• Close Mesh : check case mesh was provided with no .material or .geometry set. #84
• Close Refactor instance handling (creation / recreation / premade instance injection) #116
  • Close CubeCamera examples throw 'already added' errors -> why? #108
• Close Additional component update triggered by root_scene.userData.dirty = true in afterUpdate #111
• Close LoadedGLTF add missing props / sProps logic #120
• Close RectAreaLight call helper.updateMatrixWorld() instead of helper.update() #121
• Close RectAreaLight add width and height shorthand props #122
• Close All components need to be tested for instance injection and swapping #109
• Close Scene: verify (delete?) confusing comment / scene.userData.animations usage #94
• Close type SvelthreeAnimationFunctionReturn use or remove it #123

WebGLRenderer

• Close WebGLRenderer: refactor (rename?) set_render(...) method #85
• Close WebGLRenderer: review start_rendering() and stop_rendering() methods #86
• Close Review WebGLRenderer Component #22