add Bootstrap working example

• re-organize file structure with one directory per dialog
• add index.html file per dialog
• add bootstrap styling and dynamic cdn loading
• clean up react code and stylesheet

npm setup script update

adds force flag
"setup": "rm -f .clasp.json ..."

Update README.md

Move clasp to devDependencies

update dynamic cdn urls

Add repository field

src/client/sidebar-about-page/components/About.jsx

@@ -0,0 +1,17 @@
+import React from 'react';
+
+const About = () => (
+  <div>
+    <div>Github repo:</div>
+    <a
+      href="https://www.github.com/enuchi/React-Google-Apps-Script"
+      target="_blank"
+      rel="noopener noreferrer"
+    >
+      React + Google Apps Script
+    </a>
+    <div>-Elisha Nuchi</div>
+  </div>
+);
+
+export default About;