Add ORM models for the simulation data

- add new ORM models `ReplaySimulation` and `ReplayedOrder`
  to store the data generated by the routing simulations
- add migrations script to create the corresponding database tables
  + create "replay_simulations" and "replayed_orders" tables
  + add missing check constraints to "orders" table
  + add unique constraint to "orders" table to enable compound key
  + drop unnecessary check constraints from the "orders" table
- add tests for the new ORM models
  + add `simulation`, `replayed_order`, `make_replay_order()`, and
    `pre_order` fixtures
  + add `ReplayedOrderFactor` faker class
- fix some typos

setup.cfg

@@ -111,6 +111,8 @@ extend-ignore =
     # Let's be modern: The Walrus is ok.
     WPS332,
     # Let's not worry about the number of noqa's.
+    # Multi-line loops are ok.
+    WPS352,
     WPS402,
     # Putting logic into __init__.py files may be justified.
     WPS412,