Fix package cycle in @EnableMBeanExport

Prior to this commit, @EnableMBeanExport was declared in the
jmx.export.annotation package. This makes logical sense, but
nevertheless creates a package cycle, because @EnableMBeanExport depends
on MBeanExportConfiguration which in turn depends on context.annotation
types like @Configuration, @Bean, and @Role.

context.annotation.config.MBeanExportBeanDefinitionParser, on the other
hand already has dependencies on types in jmx.support. Together, this
means that a package cycle was introduced.

The solution to this is simple: move @EnableMBeanExport and friends from
jmx.export.annotation => context.annotation. This has been the strategy
for other @Enable annotations and for the same reasons. It also makes a
kind of logical sense: just like you find <context:mbean-export> and
<context:load-time-weaver> under the context: XML namespace, so too do
you find their @Enable* counterparts under the context.annotation
namespace.

Issue: SPR-8943

spring-context/src/main/java/org/springframework/context/annotation/EnableMBeanExport.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.jmx.export.annotation;
+package org.springframework.context.annotation;
 
 import java.lang.annotation.Documented;
 import java.lang.annotation.ElementType;
@@ -22,7 +22,7 @@ import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
-import org.springframework.context.annotation.Import;
+import org.springframework.jmx.export.annotation.AnnotationMBeanExporter;
 import org.springframework.jmx.support.RegistrationPolicy;
 
 /**

spring-context/src/main/java/org/springframework/context/annotation/MBeanExportConfiguration.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.jmx.export.annotation;
+package org.springframework.context.annotation;
 
 import java.util.Map;
 
@@ -25,12 +25,9 @@ import org.springframework.beans.factory.BeanFactory;
 import org.springframework.beans.factory.BeanFactoryAware;
 import org.springframework.beans.factory.FactoryBean;
 import org.springframework.beans.factory.config.BeanDefinition;
-import org.springframework.context.annotation.Bean;
-import org.springframework.context.annotation.Configuration;
-import org.springframework.context.annotation.ImportAware;
-import org.springframework.context.annotation.Role;
 import org.springframework.core.annotation.AnnotationAttributes;
 import org.springframework.core.type.AnnotationMetadata;
+import org.springframework.jmx.export.annotation.AnnotationMBeanExporter;
 import org.springframework.jmx.support.RegistrationPolicy;
 import org.springframework.jmx.support.WebSphereMBeanServerFactoryBean;
 import org.springframework.jndi.JndiObjectFactoryBean;