Deprecate `Constants` utility and stop using it internally

[sbrannen]

Overview

As discussed in #30846 (comment), since Constants is an outdated utility that uses reflection (which is not native-friendly), we should deprecate Constants and stop using it internally.

Related Issues

• Avoid need for reflection hints for MBeanExporter in native image #30846
• Remove obsolete native image reflection hint registration for TransactionDefinition constants #30854

Deliverables

• Deprecate Constants.
• Stop using Constants in the code base.
  • spring-context
    • MBeanExporter
  • spring-aop
    • CustomizableTraceInterceptor
  • spring-beans
    • PropertyPlaceholderConfigurer
    • XmlBeanDefinitionReader
  • spring-context-support
    • CronTriggerFactoryBean
    • SimpleTriggerFactoryBean
  • spring-jdbc
    • IsolationLevelDataSourceAdapter
    • LazyConnectionDataSourceProxy
    • IsolationLevelDataSourceRouter
  • spring-jms
    • DefaultMessageListenerContainer
    • JmsActivationSpecConfig
    • JmsAccessor
  • spring-tx
    • AbstractPlatformTransactionManager
    • DefaultTransactionDefinition

[sbrannen]

See commit 679b668 for an example of how Constants can be replaced by a simple Map in some use cases.