[keycloak-dev] Import in dist

I added a system property "keycloak.import" to the dist. This makes it possible to import settings from testrealm.json to make it easy to try out the examples without having to go through the admin console. We should delete as7-eap-demo/server and wildfly-demo/server, then start using the dists instead for the examples. To build -Prelease builds WildFly dist in dist/target/keycloak-<version> and -Prelease-as7 builds AS7 dist in dist-as7/target/keycloak-<version> (including updated Resteasy)