adapt F-UJI harvesting to handle rate limiting (HTTP 429: "Too Many Requests")

When more than 100 requests per minute are sent to the FUJI-server it responds with a HTTP status code of 429 ("Too Many Requests") and JSON that does not adhere to the expected format of FAIRscores and hence breaks the application

e.g.

{'detail': '100 per 1 minute', 'status': 429, 'title': 'Too Many Requests', 'type': 'about:blank'}