Define a new method to query historical placement data at database level

In order to support the opening of a changestream over a database name, the ShardingCatalogClient needs to provide a new method for querying the relevant content stored by config.placementHistory.

Following the lead of SERVER-68929, the signature of the new method should be:

ListOfShards getShardsThatOwnDataForDbAtClusterTime(dbName, clusterTime);