feat: init the panel of workbench

Author: wewoor

src/workbench/panel/index.tsx

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

src/workbench/panel/panel.scss

@@ -0,0 +1,8 @@
+@import '@/style/const.scss';
+
+.#{$prefix}-panel {
+    position: absolute;
+
+    // TODO just for development, this attribute should be controlled by themeService
+    border-top-color: rgb(65, 67, 57);
+}