Add a Galleon layer for embedded broker messaging

This issue is created to track the creation of a Galleon layer to make it easy to provide an embedded messaging broker.

The layer will provide a messaging-activemq subsystem with configuration like what WildFly has provided in the standard standalone-full.xml config file, except it will add configuration necessary to work nicely OOTB without the legacy security subsystem present. It will also provide ancillary configuration resources, e.g. socket-bindings. Necessary dependencies needed to support this use case, e.g. the resource-adapters subsystem, will also be provided.