Bring back deep linking in appstore to install specific versions

dashboard/src/models/AppstoreModel.js

@@ -19,6 +19,24 @@ function create(origin, accessToken) {
 
       return result.body.apps;
     },
+    async get(id, version = '') {
+      let url = `${origin}/api/v1/appstore/apps/${id}`;
+      if (version && version !== 'latest') url += `/versions/${version}`;
+
+      let error, result;
+      try {
+        result = await fetcher.get(url, { access_token: accessToken });
+      } catch (e) {
+        error = e;
+      }
+
+      if (error || result.status !== 200) {
+        console.error('Failed to get app.', error || result.status);
+        return null;
+      }
+
+      return result.body;
+    },
   };
 }