Add tests for plugin integration and improve plugin configuration handling

- Created fixtures for `services-with-cloudflare`, `services-with-deny-pages`, and `services-with-multiple-plugins`.
- Added comprehensive test cases for `CloudflarePlugin`, `DenyPagesPlugin`, and `CleanupPlugin`.
- Ensured proper configuration propagation to plugins using labels in `easymapping/__init__.py`.
- Validated multi-plugin integration and consistent output in HAProxy configuration generation.

src/tests/fixtures/services-with-deny-pages

@@ -0,0 +1,10 @@
+{
+    "192.168.1.20": {
+        "easyhaproxy.http.host": "secure.example.com",
+        "easyhaproxy.http.port": "80",
+        "easyhaproxy.http.localport": "8080",
+        "easyhaproxy.http.plugins": "deny_pages",
+        "easyhaproxy.http.plugin.deny_pages.paths": "/admin,/wp-admin",
+        "easyhaproxy.http.plugin.deny_pages.status_code": "404"
+    }
+}