Remove unused API endpoints

docs/api-documentation.md

src/metabase/api/card.clj

src/metabase/api/common/internal.clj

src/metabase/api/database.clj

src/metabase/api/dataset.clj

src/metabase/api/setting.clj

src/metabase/api/table.clj

test/metabase/api/card_test.clj

test/metabase/api/database_test.clj

test/metabase/api/dataset_test.clj

test/metabase/api/setting_test.clj

test/metabase/api/table_test.clj