Deprecate use of several bean factory methods for the same bean in a configuration class

[snicoll]

Consider the following use case:

@Configuration
public class Config {
	
	@Bean(name = "myBean")
	MyBean someBean() { ... }
	
	@Bean(name = "myBean")
	MyBean someBean(MyDependency) { ... }
}

The container accepts an override for myBean as long as it is in the same configuration class to mimic the resolution of the greediest satisfiable constructors for bean factory methods.

Such an arrangement is much better served using Optional or ObjectProvider with a single bean factory method as it makes it explicit that some argument may or may not be available.

[jhoeller]

Bean method overloading is effectively turned off by default as of 6.0, see #22609. From that perspective, formal deprecation does not seem urgent and might be better off in 7.0.

[jhoeller]

The enforceUniqueMethods flag is formally deprecated now, with the default true being the only non-deprecated behavior now. This prevents regular use of overloaded factory methods as well as @Bean method overrides with the same bean name but different method names. For the latter scenario, @Configuration(enforceUniqueMethods=false) makes it work as before in 7.0 as well (previously that kind of arrangement was not covered by the enforceUniqueMethods flag at all).