Add settings UI to enable unstable apps listing

src/views/settings.html

@@ -250,4 +250,39 @@
           </div>
       </div>
   </div>
+
+  <div class="text-left">
+    <h3>Unstable App Listing</h3>
+  </div>
+
+  <div class="card" style="margin-bottom: 15px;">
+    <div class="row">
+      <div class="col-md-12">
+        <p>
+          Besides the officially supported and tested apps, Cloudron can also install apps, which are currently in testing phase or not officially supported.
+          There is no guarantee that those apps will be updated in the future.
+          If enabled, those apps will be listed in the <a href="#/appstore">App Store</a> and marked accordingly.
+        </p>
+        <b class="text-danger">
+          Do not use those apps in any production environment.
+        </b>
+        <div class="checkbox">
+          <label>
+            <input type="checkbox" ng-model="unstableApps.enabled">Enable unstable app listing</input>
+          </label>
+          </div>
+      </div>
+    </div>
+
+    <div class="row">
+      <div class="col-md-6">
+        <span class="text-success text-bold" ng-show="unstableApps.success">Saved</span>
+      </div>
+
+      <div class="col-md-6 text-right">
+        <button class="btn btn-outline btn-primary pull-right" ng-click="unstableApps.submit()" ng-disabled="unstableApps.busy"><i class="fa fa-circle-notch fa-spin" ng-show="unstableApps.busy"></i>  Save</button>
+      </div>
+    </div>
+  </div>
+
 </div>