web-server: Add GUI button directing to index.html (#432)

Co-authored-by: Isak Jakobsson <isakj@axis.com>

Author: johan-hultberg-work

web-server/README.md

@@ -165,9 +165,9 @@ Where the expected output is
 </html>
 ```
 
-As can be seen it's HTML code, browse to web page
-`http://<AXIS_DEVICE_IP>/local/web_server_rev_proxy/my_web_server`
-for seeing it rendered.
+To view the rendered web page, click on the `Open` button of the application
+from the `Apps` tab of the device GUI. Alternatively, browse directly to
+`http://<AXIS_DEVICE_IP>/local/web_server_rev_proxy/my_web_server`.
 
 The application log can be found by either
 

web-server/app/manifest.json

@@ -9,6 +9,7 @@
 			"version": "1.0.0"
 		},
 		"configuration": {
+            "settingPage": "index.html",
 			"reverseProxy": [
 				{
 					"apiPath": "my_web_server",