Add link to Muun Wallet on About page

frontend/src/app/components/about/about.component.html

@@ -264,6 +264,13 @@
       </div>
     </a>
 
+    <a href="https://github.com/muun/apollo" target="_blank">
+      <div class="profile_photo d-inline-block" title="Muun Wallet">
+        <img class="profile_img" src="/resources/profile/muun.png" />
+        Muun
+      </div>
+    </a>
+
     <a href="https://github.com/pxsocs/warden" target="_blank">
       <div class="profile_photo d-inline-block" title="WARden Portfolio">
         <img class="profile_img" src="/resources/profile/warden.jpg" />