[feature] Query tagging capability
Since this is so google-specific, I'm not too inclined to add it at the present.
Hi @coleifer,
What do you think in general about providing a capability to add [tags for queries](https://cloud.google.com/sql/docs/postgres/using-query-insights#using-sqlcommenter:~:text=When%20you%20examine%20results%20in%20SQL%20database%20logs%2C%20they%20appear%20as%20follows)? Tagging SQL queries simplifies application troubleshooting and can be helpful for people who are using the Google Cloud SQL. Their Query Insights feature is able to parse tags and provide [application centric view](https://www.youtube.com/watch?v=qN7x3ngwz1o) to SRE. 
