refactor: Update 'core' app references to 'admin'

ui/admin/app/app.js

@@ -1,7 +1,7 @@
 import Application from '@ember/application';
 import Resolver from 'ember-resolver';
 import loadInitializers from 'ember-load-initializers';
-import config from 'core/config/environment';
+import config from 'admin/config/environment';
 
 export default class App extends Application {
   modulePrefix = config.modulePrefix;

ui/admin/app/index.html

@@ -3,14 +3,14 @@
   <head>
     <meta charset="utf-8">
     <meta http-equiv="X-UA-Compatible" content="IE=edge">
-    <title>Core</title>
+    <title>Admin</title>
     <meta name="description" content="">
     <meta name="viewport" content="width=device-width, initial-scale=1">
 
     {{content-for "head"}}
 
     <link integrity="" rel="stylesheet" href="{{rootURL}}assets/vendor.css">
-    <link integrity="" rel="stylesheet" href="{{rootURL}}assets/core.css">
+    <link integrity="" rel="stylesheet" href="{{rootURL}}assets/admin.css">
 
     <link rel="icon" type="image/svg+xml" href="{{rootURL}}logo-app.svg">
 
@@ -20,7 +20,7 @@
     {{content-for "body"}}
 
     <script src="{{rootURL}}assets/vendor.js"></script>
-    <script src="{{rootURL}}assets/core.js"></script>
+    <script src="{{rootURL}}assets/admin.js"></script>
 
     {{content-for "body-footer"}}
   </body>

ui/admin/app/router.js

@@ -1,5 +1,5 @@
 import EmberRouter from '@ember/routing/router';
-import config from 'core/config/environment';
+import config from 'admin/config/environment';
 
 export default class Router extends EmberRouter {
   location = config.locationType;