remove CACHE_MAX_DAYS feature
it simplifies the code, and it avoids periodic waste of resources to refresh entries that are already OK. If we want to refresh old entries, we can do it easily.

Requires https://github.com/huggingface/datasets-server/pull/2248 to be merged first

Closes https://github.com/huggingface/datasets-server/issues/1219 which is not needed after all.
remove CACHE_MAX_DAYS feature: it simplifies the code, and it avoids periodic waste of resources to refresh entries that are already OK. If we want to refresh old entries, we can do it easily.

Requires https://github.com/huggingface/datasets-server/pull/2248 to be merged first

Closes https://github.com/huggingface/datasets-server/issues/1219 which is not needed after all.