Restrict Kestrel server to HTTP/1 protocol in config

Added "Kestrel" section to appsettings.json to set endpoint default protocol to HTTP/1, preventing use of HTTP/2 or other protocols.

appsettings.json

@@ -5,5 +5,10 @@
       "Microsoft.AspNetCore": "Warning"
     }
   },
-  "AllowedHosts": "*"
+  "AllowedHosts": "*",
+  "Kestrel": {
+    "EndpointDefaults": {
+      "Protocols": "Http1"
+    }
+  }
 }