Currently the per-shard filtering information collections are all directly under the config database and are called config.collections and config.chunks. Since these collections are internal and somewhat transient (as in backup/restore ignores them), this naming causes confusion with similarly-named collection on the config server, which are critical because they contain the cluster routing metadata.

Because of this, we should rename them to a prefix which removes confusion with the config server's collections.

Proposed names are:

• config.cache.collections
• config.cache.chunks