Add lifecycle rule on S3 Bucket that stores DB Backups

[nodanaonlyzuul]

We have a great rake task named warper:s3_backup_db...which is called in the warper user's crontab.

It puts the development & production DB dumps into the labsdbbackup.nypl.org S3 bucket in the nypl_labs AWS account. The dumps go into /maps_db_test and /maps_db respectively.

This bucket could use a lifecycle rule to delete or glacierize the old dumps.

CCing: @nonword & @nonword