GH-6183: Fix relaxed properties for SI JMX config

[artembilan]

Fixes GH-6183 (#6183)

Since annotation based config like

@EnableIntegrationMBeanExport(defaultDomain = "${spring.jmx.default-domain:}")

is far away of RelaxedPropertyResolver in Spring Boot,
rework the IntegrationJmxConfiguration to configure required beans via raw JavaConfig

Cherry-pick to 1.4

[snicoll]

Looking at it, the original IntegrationMBeanExportConfiguration seems to do a bit more than what we have now. Either way, it's copy-pasting the code behind the annotation so I am worried about the maintenance burden of that code.

Maybe we should revisit this once SI has a public api to build the IntegrationMBeanExporter ? Thoughts @wilkinsona ?

[wilkinsona]

It seems to do everything that our previous code did; it allows the default domain and server to be configured via the environment. An API could be a nice refinement but I think we should merge this as-is.

[artembilan]

Thank you for taking a look, but, to be honest, we didn't reinvented the wheel in SI, and our IntegrationMBeanExporter environment and configuration is fully similar to MBeanExporter in the SF.

OTOH I did this new IntegrationJmxConfiguration like it is in the JmxAutoConfiguration, where that is a copy/pasting from the MBeanExportConfiguration behind EnableMBeanExport as well.

[artembilan]

By the way. Don't forget to include it into 1.3.x 😄

[snicoll]

@artembilan it seems I have issues with your stuff. Second time there is a glitch with a backport. This time I did it and forgot to push. Oh well 😢 - It's done now, thanks!