Adds buttons to test availability of server from public internet

backend/routes/api/nginx/certificates.js

@@ -68,6 +68,32 @@ router
 			.catch(next);
 	});
 
+/**
+ * Test HTTP challenge for domains
+ *
+ * /api/nginx/certificates/test-http
+ */
+ router
+ .route('/test-http')
+ .options((req, res) => {
+	 res.sendStatus(204);
+ })
+ .all(jwtdecode())
+
+/**
+ * GET /api/nginx/certificates/test-http
+ *
+ * Test HTTP challenge for domains
+ */
+ .get((req, res, next) => {
+	 internalCertificate.testHttpsChallenge(res.locals.access, JSON.parse(req.query.domains))
+		 .then((result) => {
+			 res.status(200)
+				 .send(result);
+		 })
+		 .catch(next);
+ });
+
 /**
  * Specific certificate
  *
@@ -209,7 +235,6 @@ router
 			.catch(next);
 	});
 
-
 /**
  * Download LE Certs
  *