Cleanup temporary files needed for downloading client configurations response

Cleanup temporary files needed for downloading client configurations response.

While handling the REST API call used to request client configurations, some temporary files are created and never cleaned up. Also, since the created temporary files have names generated based on the request, the potential for collision exists. Thus, the temporary files should have random names to avoid conflicts.

The request to generate the issue at hand is

GET /api/v1/clusters/c1/services/:SERVICE_NAME/components/:COMPONENT_NAME?format=client_config_tar