Use Ghost site name for subscribe form instead of admin.yml one

src/templates/GhostPost.vue

@@ -32,7 +32,7 @@
 
           <!-- Email subscribe form at the bottom of the page -->
           <section v-if="Admin.site.subscribers" class="subscribe-form">
-            <h3 class="subscribe-form-title">Subscribe to {{ Admin.site.title }}</h3>
+            <h3 class="subscribe-form-title">Subscribe to {{ $static.metadata.ghost.title }}</h3>
             <p>Get the latest posts delivered right to your inbox</p>
             <subscribeForm placeholder="youremail@example.com"/>
           </section>
@@ -163,3 +163,14 @@ export default {
     }
   }
 </page-query>
+
+<static-query>
+  query Metadata {
+    metadata {
+      ghost {
+        title
+        url
+      }
+    }
+  }
+</static-query>