Add TorusMesh

[hoontee]

PrimitiveMesh counterpart to CSGTorus3D. Required for #59077.

[hoontee]

Added tangents. All it's missing now is the resource icon.

[akien-mga]

What's the rationale for adding this as a primitive mesh? This is the kind of change that requires a proposal to discuss the use case and whether it makes sense to add things to the API.

[hoontee]

CSGTorus3D exists and this was intended to replace it internally when removing redundant CSG primitive generation code.

[hoontee]

Now that #59077 is closed this is solely to have a torus primitive mesh. CSG has one already.

[Calinou]

I tested this PR locally, it works as expected.

However, if inner_radius and outer_radius are set to the same value, mesh generation fails with the message:

ERROR: _create_mesh_array must return at least a vertex array.
   at: _update (scene/resources/primitive_meshes.cpp:53)

I suggest adding an human-readable error message by checking for the inner and outer radius' values with ERR_FAIL_COND_MSG().

The resource icon is missing because I don't know how to make one.

I made an icon for TorusMesh based on the CSGTorus3D icon 🙂

Save this file as editor/icons/TorusMesh.svg then recompile the editor to see changes: TorusMesh.svg.zip

[hoontee]

@Calinou Added your suggestions!

[akien-mga]

Thanks!