Starting with Spring Boot `2.6`, the auto-configuration
for Spring Integration introduces `poller` properties.
The `DefaultPollerProperties` and its respective `ChannelBindingAutoConfiguration` are not needed any more.
* Add `PollerConfigEnvironmentPostProcessor` to remap deprecated
`spring.cloud.stream.poller` into respective `spring.integration.poller`
properties
* Mention in the docs a deprecation move and its replacement
Related to: https://github.com/spring-projects/spring-boot/pull/27992Resolves#2233