As of Solr 8.10, SOLR-15089, there is a contrib module, s3-repository, to persist backup information to AWS S3 and certain S3-compatible object stores.

We should add this as an implementation option for SolrCloud.spec.backupRepositories.

Eventually once we remove support for Solr versions lower than 8.10, we should be able to remove the option to persist the ManagedRepository backups to S3, since users will instead be able to use SolrCloud.spec.backupRepositories[].s3.