[keycloak-dev] Testsuite now executes during normal build

I've removed Arquillian from the testsuite, and it now starts Keycloak directly using Undertow (same as AbstractKeycloakServerTest). By default the HtmlUnit WebDriver is used to make the tests run quickly (and without an annoying browser window popping up), but Chrome (-Dbrowser=chrome) or Firefox (-Dbrowser=firefox) are also supported. Let me know if anyone is having problems building and I'll sort it out ASAP.