* GH-3828: Initial Spring AOT support
Fixes https://github.com/spring-projects/spring-integration/issues/3828
* Provide an infrastructure based on a new Spring AOT engine in the latest Spring Framework
* Introduce `RuntimeHintsRegistrar` impls into modules which require some reflection,
resources or proxies and serialization available in the native image
* Mark some framework method with the `@Reflective` to make their reflection
info available in the native image, for example for SpEL or JMX invocations
* Add a `GatewayProxyBeanRegistrationAotProcessor` to register proxy interfaces
info for messaging gateways (either instance of the `GatewayProxyFactoryBean`)
* Rework `ConverterRegistrar` to not use a `beanFactory.getBeansWithAnnotation()`
since it is not available after AOT phase.
Instead, register an intermediate `IntegrationConverterRegistration` bean definition
from the `IntegrationConverterInitializer`
* Refactor `GlobalChannelInterceptorInitializer` a bit according to a new logic in the
`IntegrationConverterInitializer`
* Remove `JsonNodeWrapperToJsonNodeConverter` bean registration from the
`DefaultConfiguringBeanFactoryPostProcessor` - it is added by the `ConverterRegistrar`
into the target `ConversionService`
* Fix `ParentContextTests` respectively a `JsonNodeWrapperToJsonNodeConverter` bean removal
* Refactor `XsltPayloadTransformer` to not load a `ServletContextResource`, but just use its
name for the `xslResource` condition
* * Rework AOT support according latest changes and requirements
* Remove `@Bean` reflection since it is not needed any more
* Add `AotDetector.useGeneratedArtifacts()` condition to not register beans
one more time at runtime after AOT build phase
* Fix deprecation in the WebFlux test from the latest SF
5080fc2f45