In one case of addShard and in the ClusterServerParameterRefresher, we fetch all cluster parameters. Currently, we have to perform one call of getClusterParameter for each tenant, which scales linearly in network calls with the number of tenants. getAllClusterParameters would fetch all cluster parameters for all tenants in one network call, and return an object which looks like: {<tenant-id-1>: [{_id: "cluster-parameter-1", clusterParameterTime: <timestamp>, <param-field-1>: <val>, ...}, ...], ...}.