Improve Axon Spring Configuration (internally)

[abuijze]

The Axon Spring configuration in the axon-spring module doesn't use autoconfiguration to configure components. Instead, it actively searches the BeanFactory for definitions of a specific type.

By making the implementation used by this module a FactoryBean that implements Configurer and produces a Configuration when initialized. This allows for better guarantees on ordering of initialization of components. The FactoryBean could have setters to all optional and mandatory resources to change the Configurer's state.