[docs] Add note to highlight the ability to download a full copy of Census

[pablo-gar]

Add a note of this nature.

A copy of the Census can be downloaded locally for faster access over recurring operations, e.g. data loading for machine learning.

Shell

aws s3 --no-sign-request sync s3://cellxgene-census-public-us-west-2/cell-census/2023-12-15/soma/ ./path/to/local/folder/soma

Python

import cellxgene_census
census = cellxgene_census.open_soma(uri = "./path/to/local/folder/soma")

Suggested places to add docstrings:

• [ ] https://chanzuckerberg.github.io/cellxgene-census/_autosummary/cellxgene_census.experimental.ml.pytorch.ExperimentDataPipe.html#cellxgene_census.experimental.ml.pytorch.ExperimentDataPipe
• [ ] https://chanzuckerberg.github.io/cellxgene-census/_autosummary/cellxgene_census.experimental.ml.huggingface.CellDatasetBuilder.html
• [ ] https://chanzuckerberg.github.io/cellxgene-census/_autosummary/cellxgene_census.experimental.ml.huggingface.GeneformerTokenizer.html

Suggested places to add notebooks:

• [ ] https://chanzuckerberg.github.io/cellxgene-census/notebooks/experimental/pytorch.html