FRAPI improvements: context getters, full removal of fallback consumers, small enhancements

[Technici4n]

Add cull check and item transformation mode getter to FRAPI

New methods in RenderContext:

• isFaceCulled to perform a cull check that can be optimized and cached by the renderer.
• hasTransform, self-explanatory. Must be checked before using isFaceCulled to skip some geometry.
• itemTransformationMode to get the current item transformation mode in item contexts.

Terminally deprecate fallbackConsumer and bakedModelConsumer

The primary goal of this change is to make renderers not need to implement these fallback consumers themselves. However, their design relies on hidden context state that cannot be queried via the API. It is thus impossible to implement a fallback layer for them, and they must be deprecated, with plans for removal in 1.20.2 (EDIT: too late for that) in a follow-up PR.

Note that BakedQuadFallback.emitBlockQuads uses the newly introduced isFaceCulled and hasTransform methods to shortcut some geometric analysis.

I also removed the "vanilla quad handler" from Indigo.

Fix uvs in octagonal column test mod

Fix the uvs in the octagonal column test mod by:

• setting the cull face and thus the nominal face to leverage spriteBake for the axis-aligned quads;
• manually setting the UVs for the corner quads.