Add setup and API files with enhanced user interface and error handling

public/templates/entrys_frontend/entrys.html

@@ -1,38 +0,0 @@
-<!DOCTYPE html>
-<html lang="en">
-<head>
-  <link href="https://fonts.googleapis.com/css2?family=Roboto:wght@400;500;700&display=swap" rel="stylesheet">
-  <script type="importmap">
-    {
-      "imports": {
-        "@material/web/": "https://esm.run/@material/web/"
-      }
-    }
-  </script>
-  <script type="module">
-    import '@material/web/all.js';
-    import {styles as typescaleStyles} from '@material/web/typography/md-typescale-styles.js';
-
-    document.adoptedStyleSheets.push(typescaleStyles.styleSheet);
-  </script>
-
-  <style>
-    body {
-        display: flex;
-        justify-content: center;
-        align-items: center;
-        text-align: center;
-    }
-  </style>
-</head>
-<body>
-    <div class="content">
-        <h1 class="md-typescale-display-medium">Hello!</h1>
-        <p>Welcome to your Guestbook! Enter here your prefered username and password.</p>
-        <md-filled-text-field label="Username" type="text"></md-filled-text-field><br><br>
-        <md-filled-text-field label="Password" type="password"></md-filled-text-field><br><br>
-        <md-filled-text-field label="Repeat Password" type="password"></md-filled-text-field><br><br>
-        <md-filled-button disabled>Save</md-filled-button>
-    </div>
-</body>
-</html>