[WFLY-2238] Add model version 2.0.0 transformers to logging.

Plus maybe a few other small changes. Sorry for the multiple commits in one PR. I can put the first two in a different PR if the committers would prefer that.

The first one just moves the log4j dependency from the server to the logging subsystem which should have been done from the beginning.

The second commit just binds jboss-logmanager and the slf4j binding to aether to get rid of the message that prints in subsystem tests. This would also allow tests to control the logging output with a ```logging.properties``` file if desired.

Kabir's commit is needed to get the logging transformers working with model version 1.2.0+.

That last commit could be squashed with the 2.0.0 transformer commit, but seemed a little more appropriate as a standalone commit.