Refactored Mesh internals and formats.

-Changed how mesh data is organized, hoping to make it more efficient on Vulkan and GLES.
-Removed compression, it now always uses the most efficient format.
-Added support for custom arrays (up to 8 custom formats)
-Added support for 8 weights in skeleton data.
-Added a simple optional versioning system for imported assets, to reimport if binary is newer
-Fixes #43979 (I needed to test)

WARNING:

-NOT backwards compatible with previous 4.x-devel, will most likely never be, but it will force reimport scenes due to version change.
-NOT backwards compatible with 3.x scenes, this will be eventually re-added.
-Skeletons not working any longer, will fix in next PR.

editor/plugins/node_3d_editor_plugin.cpp

@@ -5345,7 +5345,7 @@ void Node3DEditor::_init_indicators() {
 						Vector2 ofs = Vector2(Math::cos((Math_PI * 2.0 * k) / m), Math::sin((Math_PI * 2.0 * k) / m));
 						Vector3 normal = ivec * ofs.x + ivec2 * ofs.y;
 
-						surftool->add_normal(basis.xform(normal));
+						surftool->set_normal(basis.xform(normal));
 						surftool->add_vertex(vertex);
 					}
 				}