feat: Add onquery callback. #1051
                
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Based on @porsager 's
query-statsbranch with @abustany 's fixes (to manage the 2nd/3rdonqueryinstances on thequery-level instead of globalhandlerlevel iirc).Disclaimers that:
onqueryaccepts the Query instance as-is, which can be difficult for APM tools to look at "just give me the SQL string + params", so it might be worth passing in an API that is higher-level/easier-to-consume than the raw QueryFixes #461.