MimeMappingAdd and MimeMappingRemove don't affect the runtime

While reviewing https://github.com/jbossas/jboss-as/pull/1549 I see that MimeMappingAdd and MimeMappingRemove just update the model but have no effect on the runtime services. If context.isNormalServer() == true, they should either impact a runtime service or put the server into reload-required.

Note that the current behavior may make sense during boot if the overall subsystem design has a parent resource adding a Stage.RUNTIME handler that reads child resources and uses their state to set up runtime services. But it's definitely not correct if these operations are performed independently.

As part of processing pull request 1549 I'll add TODO comments in these classes referencing this JIRA.