Remove navigation config flag

ref #4535

- don't need this any more :)

core/client/controllers/settings.js

@@ -10,8 +10,8 @@ var SettingsController = Ember.Controller.extend({
     showTags: Ember.computed('session.user.name', function () {
         return this.get('session.user.isAuthor') ? false : true;
     }),
-    showNavigation: Ember.computed('session.user.name', 'config.navigationUI', function () {
-        return this.get('session.user.isAuthor') || this.get('session.user.isEditor') || !this.get('config.navigationUI') ? false : true;
+    showNavigation: Ember.computed('session.user.name', function () {
+        return this.get('session.user.isAuthor') || this.get('session.user.isEditor') ? false : true;
     }),
     showCodeInjection: Ember.computed('session.user.name', 'controllers.feature.codeInjectionUI', function () {
         return this.get('session.user.isAuthor') || this.get('session.user.isEditor') || !this.get('controllers.feature.codeInjectionUI') ? false : true;

core/client/routes/settings/navigation.js

@@ -9,10 +9,6 @@ var NavigationRoute = AuthenticatedRoute.extend(styleBody, CurrentUserSettings,
     classNames: ['settings-view-navigation'],
 
     beforeModel: function () {
-        if (!this.get('config.navigationUI')) {
-            return this.transitionTo('settings.general');
-        }
-
         return this.currentUser().then(this.transitionAuthor());
     },
 

core/server/api/configuration.js

@@ -11,7 +11,6 @@ function getValidKeys() {
     var validKeys = {
             fileStorage: config.fileStorage === false ? false : true,
             apps: config.apps === true ? true : false,
-            navigationUI: config.navigationUI === true ? true : false,
             codeInjectionUI: config.codeInjectionUI === true ? true : false,
             version: config.ghostVersion,
             environment: process.env.NODE_ENV,