This is a first step to supporting double-precision floats in Godot.
Meshers don't need doubles because vertices, normals and UVs should
never span large enough areas while needing such amount of precision.
Besides, it costs a lot more memory and processing.
- Made a bunch of changes to comply with Godot 4 API
- Use Godot's Vector3i and add the missing stuff with helper functions
- Transvoxel uses custom attributes API, the old way would not work
- Wrap MeshOptimizer in a unique namespace (see build script why)
- Added clang-format file for the module as some rules now differ
- Prevent thirdparty code and lookup tables from being clang-formatted
- Very likely full of runtime bugs that need fixing
- VoxelBlock contains 6 optional transition meshes
- VoxelLodTerrain calculates transition masks when block visibility changes
- VoxelMesher can now specify different min and max paddings
- Fix Cube::SIDE_POSITIVE/NEGATIVE_X/Y/Z enum not matching Cube::g_side_normals
- Convert transition masks to make up for the Cube:: inconsistency for now
