MV updates should optionally wait for acknowledgement from view replicas

MV updates are currently completely asynchronous in order to provide parallelism of updates trying to acquire the partition lock. For some use cases, leaving the MV updates asynchronous is exactly what's needed.

However, there are some use cases where knowing that the update has either succeeded or failed on the view is necessary, especially when trying to allow read-your-write behavior. In those cases, we would follow the same code path as asynchronous writes, but at the end wait on the acknowledgements from the view replicas before acknowledging our write. This option should be for each MV separately, since MVs which need the synchronous properties might be mixed with MV which do not need this.