Refine Spring Integration support

[artembilan]

Fixes #1134

• Upgrade sample to the latest Spring Integration 5.5.7-SNAPSHOT
• Add maven-shade-plugin and native-maven-plugin under Windows profile
  to make native image build working on Windows.
  Se more info in Native Build Tools docs:
  https://graalvm.github.io/native-build-tools/latest/maven-plugin.html#long_classpath_and_shading_support
  This profile simply can go to the ../maven-parent/pom.xml to make all the samples working on Windows.
  Or you can remove this on merge since it might be just a noise for a broader community
• Add custom ReactorClientHttpConnector bean into the sample app, since by default a DNS resolver
  fails with NPE on Windows in native image.
  See more info in the: The ReactorClientHttpConnector must apply mapper before tcpConfiguration() spring-projects/spring-framework#27749
• Add more type nints into the IntegrationHints

[sdeleuze]

Thanks @artembilan, is Spring Integration 5.5.7-SNAPSHOT required or are we fine with 5.5.6 shipped with Spring Boot 2.6.1 and used with Spring Native 0.11.0. If 5.5.7-SNAPSHOT I think I will move integration support to Spring Native 0.11.1 to be released in a few weeks (but we can still merge this PR asap).

[artembilan]

Thanks, @sdeleuze , for review!

Well, even if Spring Boot 2.6.1 was not planned ahead to let us slip into with our releases as well, and even if Spring Boot 2.6.2 is still not planned, that fully doesn't mean we cannot merge this:

1. The fix for IntegrationHints is version independent.
2. The fix for sample contains proper version.
3. When we merge this and give it end-users, what they only would need to do is to have the same <spring-integration.version>5.5.7-SNAPSHOT</spring-integration.version> in their projects for time being.

Not sure if you have anything else in project to say what is supported and what is not, but I don't see obstacles to have this fix in the upcoming 0.11.0 release.

[sdeleuze]

Yeah I agree, I will merge a subset of this PR, thanks!

[sdeleuze]

Merged via 13272e9, good progresses!

[sdeleuze]

Feedback on the elements not integrated:

• I did 't want to integrate the Netty update before having a feedback on The ReactorClientHttpConnector must apply mapper before tcpConfiguration() spring-projects/spring-framework#27749. Rossen has since provided an update to this point which will be fixed on Windows with Spring Boot 2.6.2 I guess, so Spring Native 0.11.1.
• We should improve Windows support but via a distinct and dedicated issue for all samples with related doc, etc. See Improve Windows support documentation #1319 I created for that purpose.