Introduce an encapsulation of the various elements of the management mod...

...el

Use it support the copy-on-write/publish-on-commit semantic for ops that make management model changes

This is foundational work toward the capability/requirement stuff, which will use this new ManagementModel interface to handle the copy-on-write/publish-on-commit semantic for changes to the registry of capabilities/requirements.
It's needed.

Tests run: 10, Failures: 0, Errors: 2, Skipped: 4, Time elapsed: 3.51 sec <<< FAILURE! - in org.jboss.as.logging.LoggingSubsystemTestCase
testFailedTransformedBootOperations720(org.jboss.as.logging.LoggingSubsystemTestCase)  Time elapsed: 0.408 sec  <<< ERROR!
java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
	at org.jboss.as.model.test.ModelTestModelControllerService.waitForSetup(ModelTestModelControllerService.java:296)
	at org.jboss.as.subsystem.test.AbstractKernelServicesImpl.create(AbstractKernelServicesImpl.java:99)
	at org.jboss.as.subsystem.bridge.impl.ChildFirstClassLoaderKernelServicesFactory.create(ChildFirstClassLoaderKernelServicesFactory.java:57)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at org.jboss.as.subsystem.bridge.local.ScopedKernelServicesBootstrap.createChildClassLoaderKernelServices(ScopedKernelServicesBootstrap.java:85)
	at org.jboss.as.subsystem.bridge.local.ScopedKernelServicesBootstrap.createKernelServices(ScopedKernelServicesBootstrap.java:53)
	at org.jboss.as.subsystem.test.SubsystemTestDelegate$LegacyKernelServiceInitializerImpl.install(SubsystemTestDelegate.java:811)
	at org.jboss.as.subsystem.test.SubsystemTestDelegate$LegacyKernelServiceInitializerImpl.access$700(SubsystemTestDelegate.java:676)
	at org.jboss.as.subsystem.test.SubsystemTestDelegate$KernelServicesBuilderImpl.build(SubsystemTestDelegate.java:648)
	at org.jboss.as.logging.LoggingSubsystemTestCase.testFailedTransformedBootOperations1_2_0(LoggingSubsystemTestCase.java:291)
	at org.jboss.as.logging.LoggingSubsystemTestCase.testFailedTransformedBootOperations720(LoggingSubsystemTestCase.java:164)
Caused by: java.lang.NoSuchMethodError: org.wildfly.legacy.test.controller.subsystem_7_2_0.TestModelControllerService7_2_0.initModel(Lorg/jboss/as/controller/registry/Resource;Lorg/jboss/as/controller/registry/ManagementResourceRegistration;Lorg/jboss/as/controller/registry/Resource;)V
	at org.wildfly.legacy.test.controller.subsystem_7_2_0.TestModelControllerService7_2_0.initModel(TestModelControllerService7_2_0.java:74)
	at org.jboss.as.controller.AbstractControllerService.start(AbstractControllerService.java:180)
	at org.jboss.as.model.test.ModelTestModelControllerService.start(ModelTestModelControllerService.java:278)