attachments need to be stateful

source/RobotAPI/libraries/armem_objects/aron/Attachment.xml

@@ -35,6 +35,10 @@
             <ObjectChild key="object">
                 <armarx::armem::arondto::MemoryID />
             </ObjectChild>
+
+            <ObjectChild key="active">
+                <Bool/>
+            </ObjectChild>
         </Object>
 
         <!-- Fixed transformation between agent and articulated object -->
@@ -51,6 +55,10 @@
             <ObjectChild key="object">
                 <armarx::armem::arondto::attachment::AgentDescription />
             </ObjectChild>
+
+            <ObjectChild key="active">
+                <Bool/>
+            </ObjectChild>
         </Object>
 
     </GenerateTypes>