Dask warnings

[keflavich]

I don't know precisely where this is coming from yet, but I'm seeing these warnings spammed out - we should adopt a saner default behavior to avoid these.

/orange/adamginsburg/miniconda3/envs/python39/lib/python3.9/site-packages/dask/array/core.py:1956: PerformanceWarning: Reshaping is producing a large chunk. To accept the large
chunk and silence this warning, set the option
    >>> with dask.config.set(**{'array.slicing.split_large_chunks': False}):
    ...     array.reshape(shape)

To avoid creating the large chunks, set the option
    >>> with dask.config.set(**{'array.slicing.split_large_chunks': True}):
    ...     array.reshape(shape)Explictly passing ``limit`` to ``reshape`` will also silence this warning
    >>> array.reshape(shape, limit='128 MiB')