Update S3 bucket links of Jars downloading for Metrics in Mpack

The original link is in the 'bigtop-snapshot' which would be re-built once a week.
Then the Jars would be cleaned in the related path and files would be not found:

Connecting to bigtop-snapshot.s3.amazonaws.com (bigtop-snapshot.s3.amazonaws.com)|54.231.136.249|:80... connected.
HTTP request sent, awaiting response... 404 Not Found
2022-12-05 13:49:06 ERROR 404: Not Found.

Update the link to the bucket: repo.bigtop.apache.org which path would be permanently reserved.