Add SpringInfoContributor to expose Spring Framework/Boot version on info actuator

[madorb]

This PR provides an opt-in InfoContributor that exposes the Spring and SpringBoot versions on the info actuator endpoint.

This is controlled by the property management.info.spring.enabled=true

If true it will expose the data as:

"spring:" {
  "springBootVersion": "x.x.x",
  "springFrameworkVersion": "y.y.y"
}

though, there is likely a better naming convention, open to suggestions

[wilkinsona]

We should consider #22924 when evaluating this.

[madorb]

@wilkinsona ah, that's an interesting ticket. i actually just recently built a similar capability - as you mention there, in my app's gradle script itself. Thus it's not based on anything spring knows or the actual contents of the generated jar, but based on what gradle reports its runtime dependencies as. While familiar with the SBOM concept, I was unfamiliar with cyclonedx... it looks like it's also got a gradle plugin, so, could likely cover the vast majority of spring projects if it made sense to expose the generated SBOM.

[philwebb]

Thanks for the PR, but I think we should roll this one into #22924. If we add a dedicated SpringInfoContributor now, we're likely going to want to change it when #22924 lands.