Torch-harmonics

* Reworking distributed to allow for uneven split tensors, effectively removing the necessity of padding the transformed tensors
* Distributed SHT tests are now using unittest. Test extended to vector SHT versions
* Tests are defined in `torch_harmonics/distributed/distributed_tests.py`
* Base pytorch container version bumped up to 23.11 in Dockerfile

* Adding gradient check in unit tests
* Temporary work-around for NCCL contiguous issues with distributed SHT
* Refactored examples and documentation
* Updated SFNO example

* Adding github CI
* Changed SHT modules to convert dtype dynamically when computing the SHT/ISHT
* Bugfixes to fix importing examples

* Minor bugfixes to export SFNO code
* Readme should now render correctly in PyPI

* Added SFNO example
* Added Shallow Water Equations Dataset for SFNO training
* Cleanup of the repository and added PyPI
* Updated Readme

* Reworked distributed SHT
* Module for sampling Gaussian Random Fields on the sphere