Add user authentication and registration features

- Implement login and registration HTML templates for user authentication.
- Create user management functions in user.py for handling user data, including adding, deleting, and updating users.
- Introduce password hashing and strength checking for secure user credentials.
- Add terms of service and privacy policy pages to the website.
- Enhance main page with dynamic content based on user session status.

Website/data/appointments.json

@@ -0,0 +1,16 @@
+[
+  {
+    "id": "a-1774281965267",
+    "username": "Aiirondev",
+    "display_name": "Maximilian Gr\u00fcndinger",
+    "date": "2026-03-24",
+    "time": "10:00",
+    "subject": "Test",
+    "note": "",
+    "status": "Abgelehnt",
+    "created_at": "2026-03-23T16:06:05Z",
+    "response": "Es geht leider nicht um die von ihnen angefragte Uhrzeit, bitte versuchen sie es zwei Tage sp\u00e4ter",
+    "responded_at": "2026-03-23T16:06:52Z",
+    "responded_by": "Aiirondev"
+  }
+]

Website/data/posts.json

@@ -0,0 +1 @@
+[]

Website/data/users.json

@@ -0,0 +1,9 @@
+[
+  {
+    "username": "Aiirondev",
+    "display_name": "Maximilian Gr\u00fcndinger",
+    "password_hash": "scrypt:32768:8:1$nfN2TTigH6GNrZig$548ac55b59b2c10f2730a4a45b4140c84eba33e2719f95175c05ab1f3a157959ff7a5d11c3d38bd2ea172b0143fa3a0e0e410b8bfcc81b8d91cfbbfc12b30399",
+    "is_admin": true,
+    "created_at": "2026-03-23T16:05:42Z"
+  }
+]