Improvement: Class for Adaptation construction convenience

[EGAlberts]

      rebet_msgs::msg::Adaptation adap;

      adap.adaptation_target = static_cast<int8_t>(AdaptationTarget::LifecycleTransition);
      adap.lifecycle_adaptation = transition;
      adap.node_name = node_name;
      
   should become something like rebet::Adaptation(static_cast<int8_t>(AdaptationTarget::LifecycleTransition), node_name)