feat: Bigquery - custom Bigquery labels per query

[dtran-im]

Is your feature request related to a problem?

I do not have a way to label queries with Bigquery labels (outside of configuring the backend to apply a default query config, and thus the same labels, to every query it performs).

What is the motivation behind your request?

I would really like to adopt ibis in order to make a bunch of expensive BigQuery queries my code uses unit testable locally via another sql backend. But to do so I need Ibis to satisfy my production needs as well as my test needs. When testing with another sql backend I would not need any query specific labels, but in production in Bigquery, I find having query-specific labels very helpful when I need to evaluate the performance of my queries in aggregate across many, many runs.

Describe the solution you'd like

I'd like some way to specify Bigquery labels for particular queries, perhaps by way of allowing a custom bigquery QueryJobConfig/InsertJobConfig to be specified for that query.

Note this is not a blocker to me to the extent that this issue is. A possible but undesirable workaround would be for me to open a separate connection to bigquery for each query, each with a different default_query_job_config or default_load_job_config. And like mentioned in that issue, this is a feature very specific to the Bigquery backend. And as such, maybe it isn't quite in line with Ibis because it would be a backend-specific query configuration, rather than a backend-specific configuration. Every other backend would need to ignore this optional configuration.

What version of ibis are you running?

10.5.0

What backend(s) are you using, if any?

Bigquery

Code of Conduct

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[cpcloud]

Thanks for the issue!

Can you show an example of how you might like to use such an API? We can iterate on the design a tiny bit and see if there's a way to support your needs and/or find a suitable workaround.