(Scoped)SubscriptionHandle to unsubscribe from memory updates

Implements SubscriptionHandle returned by MemoryListener::subscribe() to unsubscribe from memory via SubscriptionHandle::release() or MemoryListener::unsubscribe(SubscriptionHandle handle) at a later point in time. Further implements ScopedSubscriptionHandle which is move-assignable via a SubscriptionHandle and automatically unsubscribes when running out of scope.

Needed for sw/armarx/skills/speech!4 (merged) (see sw/armarx/skills/speech!4 (comment 64668))

source/RobotAPI/libraries/armem/client/util/MemoryListener.cpp

@@ -183,7 +183,7 @@ namespace armarx::armem::client::util
         ARMARX_CHECK_NOT_EMPTY(memoryID.memoryName)
             << "The memoryName must be specified to subscribe";
 
-        if (component && memoryRefCount[memoryID.memoryName] == 0)
+        if (component and memoryRefCount[memoryID.memoryName] == 0)
         {
             component->usingTopic(MakeMemoryTopicName(memoryID));
         }