Implement dogma.EventRecorder interface.

[jmalloc]

/cc @Evildethow

[jmalloc]

/cc @danilvpetrov

This isn't quite as straight forward as I had hoped. TL;DR is that there's currently no way to configure an application to record a particular event type other than from within a handler (via a call to c.ProducesEvent() in an aggregate or an integration handler).

This change would require us to add a way to declare an application-level (as opposed to handler-level) event, probably by adding an ApplicationConfigurer.ProducesEvent() method. Please continue to use the "integration handler" hack in the interim.