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/openstack_utils/connect.py

@@ -1,8 +1,8 @@
-import openstack
-from openstack.connection import Connection
-
-from watcher_visio.settings import OPENSTACK_CLOUD, OPENSTACK_REGION_NAME
-
-def get_connection() -> Connection:
-    connection = openstack.connect(cloud=OPENSTACK_CLOUD, region_name=OPENSTACK_REGION_NAME)
-    return connection
+import openstack
+from openstack.connection import Connection
+
+from watcher_visio.settings import OPENSTACK_CLOUD, OPENSTACK_REGION_NAME
+
+def get_connection() -> Connection:
+    connection = openstack.connect(cloud=OPENSTACK_CLOUD, region_name=OPENSTACK_REGION_NAME)
+    return connection