SpringBoot Auto-configure JvmCpuMeterConventions bean on ProcessorMetrics

Currently we're using

@Bean
@ConditionalOnMissingBean
ProcessorMetrics processorMetrics() {
  return new ProcessorMetrics();
}

The constructor can also take a JvmCpuMeterConventions, which I think we should auto-configure if a JvmCpuMeterConventions bean is around.

The same could be done for: * JvmMemoryMetrics with JvmMemoryMeterConventions * JvmThreadMetrics with JvmThreadMeterConventions * ClassLoaderMetrics with JvmClassLoadingMeterConventions

Comment From: wilkinsona

Closing in favor of #47935. Thanks for the PR, @nosan.