OZG-7908 add List as Property value possibility

aggregation-manager-interface/src/main/protobuf/aggregatedvorgang.model.proto

@@ -53,7 +53,12 @@ message Property {
   oneof value {
     string stringValue = 2;
     Payload nestedPayload = 3;
+    ValueList valueList = 4;
   }
 }
 
+message ValueList {
+  repeated string values = 1;
+}
+
 message SubmitAggregatedVorgangResponse {}
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