Extract Side Panel from App component (#295)

* Extract Side Panel from App component

* Refactor SidePanel component

- Remove unnecessary props (we are already passing appState as a prop)
- Remove unnecessary allback (we are already passing setState)

src/element/index.ts

@@ -10,3 +10,4 @@ export { hitTest } from "./collision";
 export { resizeTest } from "./resizeTest";
 export { isTextElement } from "./typeChecks";
 export { textWysiwyg } from "./textWysiwyg";
+export { redrawTextBoundingBox } from "./textElement";