Add manual update check button to settings modal

resources/settings/settings_description.json

@@ -43,6 +43,11 @@
         "value": "automaticUpdates",
         "default": true
       },
+      {
+        "value": "manualUpdateCheck",
+        "input_type": "button",
+        "default": true
+      },
       {
         "value": "updateChannel",
         "default": 0,