feat: Implement MiniMap, Background and Controls components

src/additional-components/index.ts

@@ -0,0 +1,6 @@
+// These components are not used by React Flow directly
+// but the user can add them as children of a React Flow component
+
+export { default as MiniMap } from './MiniMap';
+export { default as Controls, ControlButton } from './Controls';
+export { default as Background } from './Background';