Dealing with violations of the cross-chain model

[RafaelAPB]

If new state would create inconsistency in model, trigger an alert and incident response mechanism.

Requirements:

1. If invalid state is created: do not send transaction. Trigger an alert to the user.
2. If invalid state is received, Trigger an alert to the user and trigger the incident response mechanism (next issue)
3. Explore what are the situations where 1) and 2) might happen in the light of our cross-chain model.
4. Reinforce cross-chain model with considerations from this presentation (please also check their slides).
5. Implement creation of the model and monitoring in the light of some suggestions in 4)

[brunoffmateus]

I will do this task.