New async projection side effect model. Closes GH-2533

New projection side effect model

Ability to publish messages in async projections

Successfully publishing events as a side effect from a single stream projection

First successful tests of applying events *during* an async projection for single stream projections!

wip: failing test for simplest possible "raise" extra events tests

Adding message outbox configuration option

src/DaemonTests/Bugs/Bug_3221_assert_on_wrong_identity_type_from_multi_stream_projection_to_slicer.cs

@@ -28,7 +28,7 @@ public void blow_up_with_helpful_exception()
             });
         });
 
-        ex.Message.ShouldContain("Invalid projection DaemonTests.Bugs.MismatchedIdentityProjection", Case.Insensitive);
+        ex.Message.ShouldContain("Id type mismatch. The projection identity type is string", Case.Insensitive);
     }
 }