IGNITE-21490 .NET: Add DataStreamer data removal

Change DataStreamer API to allow data removal:

• IDataStreamerTarget now accepts IAsyncEnumerable<DataStreamerItem<T>>
• Simplified overload accepts IAsyncEnumerable<T> as it was before
• DataStreamerItem<T> is a struct record (no allocations), accepts data item and DataStreamerOperationType enum
• DataStreamerItem factory class added to simplify generics (similar to standard library KeyValuePair.Create:
  • Constructor: new DataStreamerItem<MyEntityClass<Guid>>(entity) - entity type must be specified
  • Factory: DataStreamerItem.Create(entity) - entity type is inferred