Write an integration test for writing data to bigquery

[dbolduc]

akin to this java sample

[dbolduc]

Some prototyping from your favorite robot produced a working integration test of unknown quality:

https://github.com/googleapis/google-cloud-rust/compare/main...dbolduc:bq-write-sketch?expand=1

prompt: https://github.com/dbolduc/google-cloud-rust/blob/bb851ad7176c19c78a6c046e14cbb7e1fe0ae0db/TASK2.md

output: https://github.com/dbolduc/google-cloud-rust/blob/bb851ad7176c19c78a6c046e14cbb7e1fe0ae0db/tests/bigquery/src/lib.rs#L287-L445