Add timeline editing (#20455)

frontend/src/metabase-types/api/mocks/timeline.ts

frontend/src/metabase-types/api/timeline.ts

...lections/components/CollectionHeader/CollectionHeader.jsx

...d/src/metabase/entities/containers/EntityObjectLoader.jsx

frontend/src/metabase/entities/containers/index.js

frontend/src/metabase/entities/fields.js

frontend/src/metabase/entities/tables.js

frontend/src/metabase/entities/timeline-events.js

frontend/src/metabase/entities/timelines.js

frontend/src/metabase/icon_paths.ts

frontend/src/metabase/lib/entities.js

frontend/src/metabase/lib/redux.js

frontend/src/metabase/lib/urls.js

frontend/src/metabase/redux/requests.js

frontend/src/metabase/schema.js

frontend/src/metabase/timelines/actions.ts

...lines/components/EditEventModal/EditEventModal.styled.tsx

...se/timelines/components/EditEventModal/EditEventModal.tsx

...src/metabase/timelines/components/EditEventModal/index.ts

...components/EditTimelineModal/EditTimelineModal.styled.tsx