feat(i18n): bind angular host/player copy to shared locale catalog

frontend/angular/src/app/app.component.html

@@ -1,13 +1,20 @@
 <main class="shell">
   <header class="shell__header">
-    <h1>WPP Angular Shell</h1>
+    <h1>{{ copy('app.title') }}</h1>
     <nav>
-      <a routerLink="/host">Host</a>
-      <a routerLink="/player">Player</a>
+      <a routerLink="/host">{{ copy('app.host_nav') }}</a>
+      <a routerLink="/player">{{ copy('app.player_nav') }}</a>
     </nav>
+    <label class="locale-picker">
+      {{ copy('app.language_label') }}
+      <select [ngModel]="locale" (ngModelChange)="setLocale($event)">
+        <option value="en">English</option>
+        <option value="da">Dansk</option>
+      </select>
+    </label>
   </header>
 
-  <section class="shell__content">
+  <section class="shell__content" [attr.data-wpp-locale]="locale">
     <router-outlet></router-outlet>
   </section>
 </main>