Related to PERF-4389, we need to create a rate-limited query stats variant for a sharded cluster. I propose both a 3-shard cluster and "shard-lite" which should be able to be run more often.

Also worth fixing simultaneously. I noticed this:
> our sharded dsi variant configures the query stats collection on the mongod instead of the mongos: https://github.com/10gen/dsi/blob/1df0818771c20d5b9f5978bb5465aecc69042af7/configurations/mongodb_setup/mongodb_setup.shard-query-stats.yml#L18 (that should be under mongos_config_file not mongod)