Implement user authentication system with custom user model, views, and templates

- Created custom User model extending Django's AbstractUser.
- Added user registration, login, and profile views with corresponding templates.
- Implemented user authentication functionality and integrated Bootstrap for styling.
- Updated project settings to use the new accounts app and user model.
- Added tests for user model and admin functionality.

accounts/admin.py

@@ -0,0 +1,8 @@
+from __future__ import annotations
+
+from django.contrib import admin
+from django.contrib.auth.admin import UserAdmin
+
+from accounts.models import User
+
+admin.site.register(User, UserAdmin)