TE: Allow creating blocks smaller than 1024x1024

[Nickelony]

We can achieve this with block flags (just like diagonal geometry does).

Proof of concept:

[Nickelony]

Thinking about this more and more, it's probably not worth working on this as it would require an insane overhaul of the definition of a Block, and we should instead focus on implementing some sort of free-form-esque block creation like this (TEN only):

We could also use Volume object controls to resize / move / rotate this type of geometry, like in this example: https://github.com/MontyTRC89/Tomb-Editor/assets/20436882/c477f9d6-79e9-424c-b048-f991aa1ce803