Added XQuery Tool and refactored tools-service (#220)

Co-authored-by: Adam Bem <adam.bem@zoho.eu>
Reviewed-on: #220
Reviewed-by: Mikolaj Widla <widlam@noreply.example.com>

Backend-libXML/main.py

@@ -54,7 +54,7 @@ def process_xml(request: request, type: str) -> str:
         code = 400
     finally:
         exec_time = (time.time_ns() - start) / 10**6
-        response_json['time'] = f"{exec_time:.03f}"
+        response_json['duration'] = f"{exec_time:.03f}"
         response_json['processor'] = "libxml2 over lxml"
         return json.dumps(response_json), code