deposit: Deal with rate limit during get queries

We currently have some icing alerts about 429 response [1]. The current code is not able to deal with it. So, this reuses the retry decorator used in some other parts of the swh base code to retry with a backoff when this occurs. This should fix the current failures.

This got tested for the staging end-to-end with success. The check got back to green.

[1]

DEPOSIT CRITICAL - Getting the list of metadata returned code 429:
b'{"exception":"Throttled",​"reason":"Request was throttled. Expected available in 16
seconds."}'

Refs. swh/infra/sysadm-environment#5129 (closed)