Enable adding support for AES-GCM (http://www.w3.org/2009/xmlenc11#aes128-gcm)...

Enable adding support for AES-GCM (http://www.w3.org/2009/xmlenc11#aes128-gcm) in incoming SAML messages. Add sample for adding AES-GCM support.

Samples/SampleAesGcmStartupNetCore31/Properties/launchSettings.json

+{
+  "iisSettings": {
+    "windowsAuthentication": false, 
+    "anonymousAuthentication": true, 
+    "iisExpress": {
+      "applicationUrl": "http://localhost:50565",
+      "sslPort": 0
+    }
+  },
+  "profiles": {
+    "IIS Express": {
+      "commandName": "IISExpress",
+      "launchBrowser": true,
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development"
+      }
+    },
+    "SampleAesGcmStartupNetCore31": {
+      "commandName": "Project",
+      "launchBrowser": true,
+      "applicationUrl": "http://localhost:5000",
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development"
+      }
+    }
+  }
+}