Inroduce 'commons-vscode' to share typescript code between vscode-exts

vscode-extensions/commons-vscode/src/index.ts

@@ -0,0 +1,3 @@
+import {testUtil} from './launch-util';
+
+export {testUtil};

vscode-extensions/commons-vscode/src/launch-util.ts

@@ -0,0 +1,5 @@
+import * as code from 'vscode';
+
+export function testUtil() {
+    return 'this is a test';
+}