docs(aio): add angular.schule to resources (#22164)

adds a link to our website. many thanks for reviewing this

PR Close #22164

aio/content/marketing/resources.json

@@ -652,6 +652,13 @@
             "rev": true,
             "title": "We Are One Sàrl",
             "url": "https://weareone.ch/courses/angular/"
+          },
+          "angular-schule": {
+            "desc": "Angular onsite training and public workshops in Germany from the authors of the German Angular book. We also regularly post articles and videos on our blog (in English and German language).",
+            "logo": "https://angular.schule/assets/img/brand.svg",
+            "rev": true,
+            "title": "Angular.Schule (German)",
+            "url": "https://angular.schule/"
           }
         }
       }