Pass chunks as a parameter to save_array

[jcfaracco]

I'm having issues to save a Numpy array with chunks and load them as a Dask Array with different chunks.

Some example (current behavior):

import dask.array as da
import numpy as np
import zarr

array = np.random.random(10000)
zarr.save_array("/tmp/data.zarr", data)
darray = da.from_zarr("/tmp/data.zarr/")

print(ddata.chunks)     # Output ((10000,),)

Whis this change, users should be able to define the chunk to save.

import dask.array as da
import numpy as np
import zarr

array = np.random.random(10000)
zarr.save_array("/tmp/data.zarr", data, chunks=(100))
darray = da.from_zarr("/tmp/data.zarr/")

print(ddata.chunks)     # Output ((100,),)

This PR does not have a unit test because the unit tests for save_array are with comments.

TODO:

• Add unit tests and/or doctests in docstrings
• Add docstrings and API docs for any new/modified user-facing classes and functions
• New/modified features documented in docs/user-guide/*.rst
• Changes documented as a new file in changes/
• GitHub Actions have all passed
• Test coverage is 100% (Codecov passes)