Support asynchronous non-market orders (#8946)

* Add 'asynchronous' parameter to trading api

* Add regression algorithms

* More fixes for asynchronous orders

* Fix failing unit tests

* Fix failing unit tests

* Add multiple orders requests in transaction handler

Make each transaction thread handle requests corresponding to the same order

* Refactor order state machine in BrokerageTransactionHandler

Now using a single dictionary to hold orders and their state, either pending for submission, open or closed.

* Revert: remove complete orders from new state machine in BTH

* Add order ticket to new BTH open orders state machine

* Run syn in Backtesting transaction handler for new orders submission

* Remove OpenOrderState.SubmissionPending property

* Add Security to OpenOrderState

* Minor fix

* Cleanup

* Some cleanup in BTH

* Cleanup

* Minor fix

* Minor unit test fix

* Minor fix

* Make Brokerage.ConcurrencyEnable property virtual

* Minor change

* Cleanup

* Add 'asynchronous' parameter to SetHoldings api

* Improve regression algorithms

Algorithm.Python/OrderTicketAssignmentDemoAlgorithm.py

@@ -42,8 +42,10 @@ class OrderTicketAssignmentDemoAlgorithm(QCAlgorithm):
         ticket = order_event.ticket
         if ticket is None:
             raise AssertionError("Expected order ticket in order event to not be null")
-        if order_event.status == OrderStatus.SUBMITTED and self.ticket is not None:
-            raise AssertionError("Field self.ticket not expected no be assigned on the first order event")
+        if self.ticket is None:
+            raise AssertionError("Expected the ticket to have been returned by the MarketOrder call")
+        if ticket.order_id != self.ticket.order_id:
+            raise AssertionError("Expected the ticket in the order event to be the same instance as the one returned by MarketOrder")
 
         self.debug(ticket.to_string())