Renamed frontend/web/app to site

- This leaves us room to bring the frontend app in as app.js

core/bridge.js

@@ -88,7 +88,7 @@ class Bridge {
     reloadFrontend() {
         const apiVersion = this.getFrontendApiVersion();
         debug('reload frontend', apiVersion);
-        const siteApp = require('./frontend/web/app');
+        const siteApp = require('./frontend/web/site');
         siteApp.reload({apiVersion});
     }
 }

core/frontend/web/index.js

@@ -1 +1 @@
-module.exports = require('./app');
+module.exports = require('./site');