Refactor Django settings module and environment configuration

- Move settings to a modular configuration structure
- Update environment variables in .env.example
- Modify DJANGO_SETTINGS_MODULE references across project files
- Simplify and standardize environment variable naming

.env.example

@@ -1,22 +1,23 @@
-DEBUG=True
-SECRET_KEY=
+DJANGO_DEBUG=False
+SECRET_KEY=""
 POSTGRES_DATABASE=
 POSTGRES_USER=
 POSTGRES_PASSWORD=
 POSTGRES_HOST=
 POSTGRES_PORT=
-
-ALLOWED_HOSTS="localhost"
-CSRF_TRUSTED_ORIGINS="http://localhost"
 DJANGO_SECURE_SSL_REDIRECT=False
-CSRF_COOKIE_DOMAIN="http://localhost"
+DJANGO_SETTINGS_MODULE="apibase.django.local"
+ALLOWED_HOSTS=""
+CSRF_TRUSTED_ORIGINS=""
+CSRF_COOKIE_DOMAIN=""
 
-EMAIL_HOSTNAME=
+EMAIL_HOSTNAME=""
 EMAIL_PORT=
 EMAIL_USERNAME=
 EMAIL_PASSWORD=
-FRONTEND_URL=
 
-PAYMENT_VERIFY_BASE_URL=
-SMS_API_URL=
-SMS_API_KEY=
+PAYMENT_VERIFY_BASE_URL=""
+FRONTEND_URL=""
+
+SMS_API_URL=""
+SMS_API_KEY=""