Today, the initialization of config.placementHistory is implemented through a ShardingCatalogManager method that provides limited resilience to step down events of the config server and ability to serialize with incompatible operations - namely:

1. targeting queries from change stream readers
2. commit of DDL operations & chunk migrations
3. topology changes
4. removal of disposable documents of config.placementHistory.

The InitializePlacementHistoryCoordinator introduced with SERVER-108943 is meant to close the gap.

The objective of this ticket is to modify the coordinator to ensure proper serialization with inflight reads supporting the targeting of V2 change stream readers.