Adding SSL Support for the AS integration.

In preparation to add transport guarantee and client-cert authentication support this pull request adds the ability to define a https listener in addition to the http listener in the undertow subsystem.

The first commit is to split out the core undertow functionality from the http listener - this area still needs some further discussions to decide how multiple definitions of a container may be handled.

The second commit adds the ability to define a https listener, this makes use of the existing security realms so is consistent with the definitions we use to enable TLS on the Remoting connectors and for the management interfaces.

To make use of the https listener I first define a new realm that uses the key and trust stores previously added to the undertow project: -

            <security-realm name="UndertowRealm">
                <server-identities>
                    <ssl>
                        <keystore path="/home/darranl/src/jbossas7/undertow/core/src/test/resources/server.keystore" keystore-password="password" />
                   </ssl>
                </server-identities>
                <authentication>
                    <truststore path="/home/darranl/src/jbossas7/undertow/core/src/test/resources/server.truststore" keystore-password="password" />
                </authentication>
            </security-realm>

Next the https-listener can be added to the undertow subystem and reference the realm: -

            <https-listener name="default" socket-binding="https" security-realm="UndertowRealm" />