Porting `so3.clebsch_gordan` and `so3.spherical_harmonics` to `e3nn/e3nn-jax`

[mitkotak]

@atharvchagi This might be a good first issue to get your feet wet. If you look at e3nn/e3nn-jax, there's a lot of complains about not supporting lmax>=10 spherical_harmonics. I think the machinery should help us resolve that issue since we can precompute, store it as .npz and then call it again. Similar story with cg coefficients as well

TODOS

• Update the test cases here to get a feel for how the API looks
• Update e3nn/e3nn-jax.spherical_haromonics
• Similar process for e3nn/e3nn-jax.clebsch_gordan

I know this is pretty vague. If you are interested can provide more details :)

[atharvchagi]

Hi Mit. Thanks, I am interested, could you provide more details please?