[firestore-bigquery-export] support bigquery integer range partitioning

### [REQUIRED] Step 2: Extension name

This feature request is for extension: firestore-bigquery-export

### What feature would you like to see?

Support bigquery integer range partitioning in the extension

### How would you use it?

I have a customerId property at the root of my firestore documents. Partitioning on customerId (BQ integer range partitioning) would be much more useful than partitioning on a date field. Most of my BQ SQL request will retrieve all documents for one customer and a date partitioning does not bring any value.