Add texcoord and tangent (tx, ty, ux, uy, uz) calculated values to libsoy/src/bodies/Sphere.gs.

Texcoords should map, similar to Box, such that the cooresponding tangents also work with a cubemap (which uses position rather than texcoord values) when applied. This will require some clever "folding", there are many ways to do this which are equally correct.

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