Figure out a better way of dealing with TaskConfigs in client queries

The current approach of returning TaskConfigs from getTasksStatus RPC is not ideal from perf standpoint. While ScheduledTask->AssignedTask instantiation carries a specific meaning for every instance, the TaskConfigs are all identical in majority of the cases and just riding alone slowing down the RPC by their often enormous size. This creates a fertile ground for workarounds like AURORA-539.

Consider a normalized way of dealing with TaskConfigs that would avoid unnecessary repetition. E.g.: detaching TaskConfigs from the AssignedTask and serving them over a dedicated "getTaskConfigs" RPC.