Jaxdecomp

* Changes
* jaxDecomp works without MPI and using only JAX as backend
* with mesh is no longer required (will be deprecated by JAX)
* Added support for fftfreq
* Added testing for all functions
* Added static typing and checked with mypy

* Changes
* Fixed bug with Halo
* Added joss paper

* Changes
* New version compatible with JAX 0.4.30
* jaxDecomp now works in a multi-host environment
* Added custom partitioning for FFTs
* Added custom partitioning for halo exchange
* Added custom partitioning for slice_pad and slice_unpad
* Add example for multi-host FFTs in `examples/jaxdecomp_lpt.py`

* Changes
* Added utility to run autotuning

Initial pre-release, include support for parallel ffts and halo exchange