Implement RaggedArray.from_xarray()

[milancurcic]

• Implementation
• Test
• Docs

Closes #44

[philippemiron]

I added a test to check if the dimension names are not "traj" and "obs". Also, you can do from clouddrift import RaggedArray directly because __init__.py imports automatically the class in the dataformat.py.

[philippemiron]

Actually, I have two more comments to discuss:

• wouldn't it be more useful also to have the default parameters (dim_traj: str = "traj", dim_obs: str = "obs") on the from_netcdf method?
• we could also copy/paste this wrapper and call it from_zarr and it should work seamlessly

[milancurcic]

Thanks, Philippe.

On the first point, yes, it would be more useful, but I chose to leave it alone for now because we're considering removing readers and writers for file formats (parquet and netcdf). The rationale is that the users will work with data in xarray or awkward, and they can read and write from and to files from those libraries.

And similar for zarr. Most likely we'll just show the user how to do it from xarray. Less likely, you're right, it can be the same wrapper as from_netcdf.

Another reason that it wouldn't be part of this PR is that I want to keep PRs small and focused (single feature).

[milancurcic]

Thank you for the review!