Refactor E2E tests and configuration format

- Replaced `easymapping` configuration with `containers` for better maintainability and clarity.
- Introduced `DockerComposeFixture` class in `utils.py` to manage Docker Compose lifecycle and smart build strategy.
- Enhanced YAML-to-environment variable conversion in `ContainerEnv` for dynamic configuration support.
- Updated HAProxy configurations and test fixtures to reflect the new format.
- Improved test coverage for YAML parsing, environment variable handling, and HAProxy config generation.

docs/Plugins/jwt-validator.md

@@ -228,13 +228,12 @@ spec:
 
 ```yaml
 # /etc/haproxy/static/config.yaml
-easymapping:
-  - host: api.example.com
-    port: 443
-    container: api-service:8080
-    plugins:
-      - jwt_validator
-    plugin_config:
+containers:
+  "api.example.com:443":
+    ip: ["api-service:8080"]
+    ssl: true
+    plugins: [jwt_validator]
+    plugin:
       jwt_validator:
         algorithm: RS256
         issuer: https://auth.example.com/