[WFLY-206] JMS access over HTTP

* bump messaging subsystem XML schema to urn:jboss:domain:messaging:1.4
* bump messaging management version to 2.0.0
* add servlet-connector resource to hornetq-server to define a connector
  that will connect to the HornetQ server over HTTP by tunneling through
  a Servlet
* add to the messaging subsystem XML config a servlet-connector and a
  JMS ConnectionFactory that uses it.
* add an optional dependency to the org.jboss.as.web-common module to be able
  to deploy the servlet from the org.jboss.as.messaging module
* add test JMSClientTestCase#testJMSOverHTTPWithServlet()
[WFLY-1350] Make modular build reusable by external projects