Add support for qualifiers into the Spring DSL

Qualifiers are a powerful concept in Spring, but not supported by the DSL despite being a first-class citizen in the XML configuration. Thus, an XML snippet like this:

<bean class="org.example.MyBean">
<qualifier value="a_bean">
</bean>

becomes messy DSL code like this (imports assumed for readability):
myBean(MyBean)

{ bean -> bean.beanDefinition.addQualifier(new AutowireCandidateQualifier(Qualifier, 'a_bean ')) }

I suggest adding a method to org.codehaus.groovy.grails.commons.spring.DefaultBeanConfiguration to streamline this process. Something like this:

public void addQualifier(String name)

{ addQualifier(Qualifier.class, name) }

public void addQualifier(Class qualifierClass, name)

{ getBeanDefinition.addQualifier(new AutowireCandidateQualifier(qualifierClass, name)) }

Which would then allow the DSL code to be:

myBean(MyBean)

{ bean -> bean.addQualifier('a_bean ') }

or (for typed-base qualifiers):

myBean(MyBean)

{ bean -> bean.addQualifier(MyQualifierMarker, 'a_bean') }