Add new :min & :max aggregation types #1660

frontend/src/lib/query.js

frontend/src/lib/schema_metadata.js

src/metabase/driver/druid/query_processor.clj

src/metabase/driver/generic_sql/query_processor.clj

src/metabase/driver/mongo/query_processor.clj

src/metabase/driver/query_processor/expand.clj

src/metabase/driver/query_processor/interface.clj

src/metabase/metabot.clj

test/metabase/driver/query_processor_test.clj

test/metabase/driver/timeseries_query_processor_test.clj