Prepend info about query execution to SQL

src/metabase/api/dataset.clj

src/metabase/driver.clj

src/metabase/driver/bigquery.clj

src/metabase/driver/druid/query_processor.clj

src/metabase/driver/generic_sql/query_processor.clj

src/metabase/driver/mongo/query_processor.clj

src/metabase/query_processor.clj