Merge pull request #6848 from metabase/query-cancellation

project.clj

src/metabase/api/card.clj

src/metabase/api/common.clj

src/metabase/api/dataset.clj

src/metabase/driver/druid.clj

src/metabase/driver/druid/query_processor.clj

src/metabase/driver/generic_sql/query_processor.clj

src/metabase/driver/presto.clj

src/metabase/middleware.clj

test/metabase/api/common_test.clj

test/metabase/driver/druid_test.clj

test/metabase/driver/presto_test.clj

test/metabase/middleware_test.clj

...metabase/query_processor_test/query_cancellation_test.clj

test/metabase/test/util.clj