Since an `IntegrationComponentSpec` is a `FactoryBean`, all it's target
callbacks and lifecycle is controlled over a `FactoryBean`.
* Add `SmartLifecycle` for the `IntegrationComponentSpec` to delegate
lifecycle hooks to the `target` if necessary
* Refactor `IntegrationComponentSpec` to be an `AbstractFactoryBean`
which is a central place for the `FactoryBean`, `InitializingBean` and
`DisposableBean` interfaces
**Cherry-pick to 5.0.x**
690a2c3c3e