Updated to handle new Config API response

refs: https://github.com/TryGhost/Team/issues/510

- The config API has been changed to return the full hostSettings key, not just the billing URL
- This has been done because we are adding more config, and it's easier to reason about if Admin has the same config as server
- Proxying each value also requires multiple updates to the API each time
- This updates all the places where the old values were used

ghost/admin/app/components/gh-nav-menu/main.js

@@ -39,7 +39,7 @@ export default Component.extend(ShortcutsMixin, {
     showTagsNavigation: or('session.user.isOwnerOrAdmin', 'session.user.isEditor'),
     showMenuExtension: and('config.clientExtensions.menu', 'session.user.isOwner'),
     showScriptExtension: and('config.clientExtensions.script', 'session.user.isOwner'),
-    showBilling: computed.reads('config.billingUrl'),
+    showBilling: computed.reads('config.hostSettings.billing.enabled'),
 
     init() {
         this._super(...arguments);

ghost/admin/app/controllers/application.js

@@ -12,7 +12,7 @@ export default Controller.extend({
     settings: service(),
     ui: service(),
 
-    showBilling: computed.reads('config.billingUrl'),
+    showBilling: computed.reads('config.hostSettings.billing.enabled'),
     showNavMenu: computed('router.currentRouteName', 'session.{isAuthenticated,user.isFulfilled}', 'ui.isFullScreen', function () {
         let {router, session, ui} = this;
 

ghost/admin/app/services/billing.js

@@ -14,7 +14,7 @@ export default Service.extend({
     init() {
         this._super(...arguments);
 
-        if (this.config.get('billingUrl')) {
+        if (this.config.get('hostSettings.billing.url')) {
             window.addEventListener('message', (event) => {
                 if (event && event.data && event.data.route) {
                     this.handleRouteChangeInIframe(event.data.route);
@@ -38,7 +38,7 @@ export default Service.extend({
     },
 
     getIframeURL() {
-        let url = this.config.get('billingUrl');
+        let url = this.config.get('hostSettings.billing.url');
 
         if (window.location.hash && window.location.hash.includes(this.get('billingRouteRoot'))) {
             let destinationRoute = window.location.hash.replace(this.get('billingRouteRoot'), '');