refactor: Move App component to DbMan directory and update imports

Author: devin-grabtaxi

src/App/index.tsx renamed to src/DbMan/index.tsx

@@ -1,7 +1,7 @@
 import React from 'react';
 import ReactDOM from 'react-dom/client';
 import './index.css';
-import App from './App/index';
+import App from './DbMan';
 import reportWebVitals from './reportWebVitals';
 
 const root = ReactDOM.createRoot(