Merge pull request #1856 from metabase/serialize-cards-as-hashes

frontend/src/card/card.controllers.js

frontend/src/card/card.module.js

frontend/src/components/ColumnarSelector.jsx

frontend/src/components/CreateDashboardModal.jsx

frontend/src/components/DashboardsDropdown.jsx

frontend/src/components/ModalContent.jsx

frontend/src/components/PasswordReveal.jsx

frontend/src/components/QuestionSavedModal.jsx

frontend/src/components/RadioSelect.jsx

frontend/src/components/SaveQuestionModal.jsx

frontend/src/components/SortableItemList.jsx

frontend/src/components/Toggle.jsx

frontend/src/components/Triggerable.jsx

frontend/src/css/core/base.css

frontend/src/lib/card.js

frontend/src/query_builder/CardFavoriteButton.jsx

frontend/src/query_builder/DataReference.jsx

frontend/src/query_builder/DataReferenceField.jsx

frontend/src/query_builder/DataReferenceMain.jsx

frontend/src/query_builder/DataReferenceQueryButton.jsx