Actually make dask.distributed optional #22

[elbdmi]

• Added a check to make psutil and dask.distributed optional to improve flexibility.
• Introduced a flag (dask_distributed_available) to skip dask-related multiprocessing setup if dependencies are missing.
• Provided a warning message if dask.distributed or psutil are not available.
• Updated the code to run only dask-specific logic when the necessary modules are present.

[elbdmi]

@leifdenby now it is ready

[leifdenby]

Perfect! Thank you for doing this :)