Also separated Light2D in PointLight2D and DirectionalLight2D.
Used PointLight2D because its more of a point, and it does not work
the same as OmniLight (as shape depends on texture).
Added a few utility methods to Rect2D I needed.
-Allows merging several 2D objects into a single draw operation
-Use current node to clip children nodes
-Further fixes to Vulkan barriers
-Changed font texture generation to white, fixes dark eges when blurred
-Other small misc fixes to backbuffer code.
-Removed normal/specular properties from nodes
-Create CanvasTexture, which can contain normal/specular channels
-Refactored, optimized and simplified 2D shaders
-Use atlas for light textures.
-Use a shadow atlas for shadow textures.
-Use both items aboves to make light rendering stateless (faster).
-Reorganized uniform sets for more efficiency.
Which means that reduz' beloved style which we all became used to
will now be changed automatically to remove the first empty line.
This makes us lean closer to 1TBS (the one true brace style) instead
of hybridating it with some Allman-inspired spacing.
There's still the case of braces around single-statement blocks that
needs to be addressed (but clang-format can't help with that, but
clang-tidy may if we agree about it).
Part of #33027.
Using `clang-tidy`'s `modernize-use-default-member-init` check and
manual review of the changes, and some extra manual changes that
`clang-tidy` failed to do.
Also went manually through all of `core` to find occurrences that
`clang-tidy` couldn't handle, especially all initializations done
in a constructor without using initializer lists.
