Feature: Action System (#298)

* Add Action System

- Add keyboard test
- Add context menu label
- Add PanelComponent

* Show context menu items based on actions

* Add render action feature

- Replace bringForward etc buttons with action manager render functions

* Move all property changes and canvas into actions

* Remove unnecessary functions and add forgotten force update when elements array change

* Extract export operations into actions

* Add elements and app state as arguments to `keyTest` function

* Add key priorities

- Sort actions by key priority when handling key presses

* Extract copy/paste styles

* Add Context Menu Item order

- Sort context menu items based on menu item order parameter

* Remove unnecessary functions from App component

src/actions/actionSelectAll.ts

@@ -0,0 +1,13 @@
+import { Action } from "./types";
+import { META_KEY } from "../keys";
+
+export const actionSelectAll: Action = {
+  name: "selectAll",
+  perform: elements => {
+    return {
+      elements: elements.map(elem => ({ ...elem, isSelected: true }))
+    };
+  },
+  contextItemLabel: "Select All",
+  keyTest: event => event[META_KEY] && event.code === "KeyA"
+};