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.

.dockerignore

@@ -1,23 +1,23 @@
-.git
-.gitignore
-__pycache__
-*.pyc
-*.pyo
-*.pyd
-.env
-.venv
-venv/
-env/
-.vscode
-.idea
-*.log
-*.sqlite3
-static/
-media/
-node_modules/
-npm-debug.log*
-yarn-debug.log*
-yarn-error.log*
-Dockerfile
-docker-compose.yml
-README.md
+.git
+.gitignore
+__pycache__
+*.pyc
+*.pyo
+*.pyd
+.env
+.venv
+venv/
+env/
+.vscode
+.idea
+*.log
+*.sqlite3
+media/
+node_modules/
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+Dockerfile
+docker-compose.yml
+README.md
+clouds.yaml