Use new Weight Message for termination detection

[rcschrg]

In GitLab by @mnebel-wenner on Jun 13, 2022, 13:26

Currently the message weight is appended to a negotiation message. In order to make the message serializable, the field messag_weight has hence to be added to the constructor of the negotiation message. I would prefer a design, in which the message weight is not part of the negotiation message but sent seperatly