JIRA: https://jira.springsource.org/browse/INT-3284
* Introduce `IntegrationConfigurationBeanFactoryPostProcessor`, `IntegrationConfigurationInitializer`
* Apply `IntegrationConfigurationInitializer` and 'spring.factories' for HTTP and Security modules
INT-3284: Address PR's comments
JIRA: https://jira.springsource.org/browse/INT-3287
* Fix package tangle (INT-3287)
* Apply `IntegrationConfigurationInitializer` for `MBeanExporterHelper`
* Previously, there was a separate `ChannelSecurityInterceptorBeanPostProcessor`
for each `ChannelSecurityInterceptor` whereas now, there is one `ChannelSecurityInterceptorBeanPostProcessor`
that processes all interceptors
INT-3284 Refactoring around config package tangle