PLT-3408 Add SiteURL to config.json (#3692)

* PLT-3408 Changed serverside code to get the service's URL from config.json

* PLT-3408 Changed most clientside code to use the SiteURL config setting instead of window.location

* PLT-3408 Changed default SiteURL to be autodetected

webapp/components/needs_team.jsx

@@ -73,7 +73,7 @@ export default class NeedsTeam extends React.Component {
         // Go to tutorial if we are first arriving
         const tutorialStep = PreferenceStore.getInt(Preferences.TUTORIAL_STEP, UserStore.getCurrentId(), 999);
         if (tutorialStep <= TutorialSteps.INTRO_SCREENS) {
-            browserHistory.push(Utils.getTeamURLNoOriginFromAddressBar() + '/tutorial');
+            browserHistory.push(TeamStore.getCurrentTeamRelativeUrl() + '/tutorial');
         }
     }