Redesign idea (#343)

* Redisign idea

* Code cleanup

* Fixed to right container

* Reoredered layout

* Reordering panels

* Export dialog

* Removed redunant code

* Fixed not removing temp canvas

* Fixed preview not using only selected elements

* Returned file name on export

* Toggle export selected/all elements

* Hide copy to clipboard button if no support of clipboard

* Added border to swatches

* Fixed modal flickering

src/actions/types.ts

@@ -52,7 +52,7 @@ export interface ActionsManagerInterface {
   ) => { label: string; action: () => void }[];
   renderAction: (
     name: string,
-    elements: ExcalidrawElement[],
+    elements: readonly ExcalidrawElement[],
     appState: AppState,
     updater: UpdaterFn
   ) => React.ReactElement | null;