Changed Integration Events to be considered similar to DomainEvents and manageable from the DomainEntity

[fabiomaistro]

Description

• IntegrationEvent(s) are now a special type of DomainEvent(s)
• It's now possible to raise Integration Events from domain entities inheriting from DomainEntity
• It's now possible to register an IntegrationEventDispatcher and integration events will be dispatched BEFORE the SaveChanges happen in EF

Notes:

• Given that integration events are just a special version of domain events, the activation of integration events implies also the activation of domain events
• At the current stage, integration events are NOT persisted in the database like domain events
• At the current stage, it's NOT possible to inject the DomainContext within the IntegrationEventDispatcher implementation (that will cause Autofac to raise a StackOverflowException)

Motivation and Context

The change is motivated by the idea that it should be possible to raise integration events before domain entities are saved in the database in a similar way to what it's done for domain events. The dispatching of the integration events and its handling are responsibility of the user of these libraries.

Testing

Tested in a specific branch of Obelisk.
Usage example: