BigQuery Connector - Ability to choose the "Partitioned on field"

[timorkal]

Right now the default "Partitioned on field" is _airbyte_extracted_at, which might be good for some use cases.
But in my usecase it's not giving me the performance that I need as I have my own column which is "created_at" where most of the queries are using, and I would like to Partition my table based on this.
The _airbyte_extracted_at is also relevant only for the day of the "extraction" which is not ideal, but the "created_at" is relevant to the real date when the data was added to my source table originally.