Refactor Docker setup and add mock data support

- Updated .dockerignore and .gitignore for better file management.
- Introduced .env.example for environment variable configuration.
- Added docker-compose.dev.yml for development with mock data and live reload.
- Enhanced Dockerfile to include necessary dependencies and entrypoint script.
- Created mock_data.py to provide sample data for testing without OpenStack/Prometheus.
- Added unit tests for template filters in dashboard.
- Cleaned up various files for consistency and improved readability.

dashboard/urls.py

@@ -1,6 +1,6 @@
-from django.urls import path
-from . import views
-
-urlpatterns = [
-    path('', views.index, name='index'),
+from django.urls import path
+from . import views
+
+urlpatterns = [
+    path('', views.index, name='index'),
 ]