feat: init the activity bar of workbench

Author: wewoor

src/workbench/activityBar/activityBar.scss

@@ -0,0 +1,10 @@
+@import '@/style/const.scss';
+
+.#{$prefix}-activityBar {
+    position: absolute;
+    width: 48px;
+    height: 100%;
+    z-index: 1;
+    // TODO temp style, just for development
+    background-color: rgb(51, 51, 51);
+}

src/workbench/activityBar/index.tsx

@@ -0,0 +1,15 @@
+import * as React from 'react';
+
+import { prefixClaName } from '@/common/className';
+
+import './activityBar.scss';
+
+export const ActivityBar: React.FunctionComponent = function() {
+    return (
+        <div className={prefixClaName('activityBar')}>
+            ActivityBar
+        </div>
+    );
+};
+
+export default ActivityBar;