python(chore): csv example ingestion

[niliayu]

Adds an example of how to ingest data from a CSV file. This example is simple and makes a few assumptions (e.g. channels are all doubles), but hopefully is easy enough to understand an expand from for other uses.

[solidiquis]

Some small changes! There were some things I did in the original example that aren't suitable to show to users in official examples so we'll get those cleaned up :)

[solidiquis]

Just a couple tiny nits and one final request: Would you mind truncating the CSV to just have 50 rows? The CSV as is is quite large and it'll blow up our repo size. 50 rows will get the same point across :)

[solidiquis]

LGTM! Thanks for iterating with me!

[niliayu]

Thanks for the quick feedback, super helpful in learning the patterns here!