Validate 2.x domain topology transaction messages

The domain topology manager distributes the topology state through domain topology messages to all registered and active members. This class is used to verify the correctness of the given signature.

Some care is required when validating the signature, as the key used by the domain topology dispatcher is actually defined by the state that it changes.

When a new participant connects for the first time, it will receive a first message which is self-consistent, where the message is signed by a key for which we get all topology transactions in the message itself.

Therefore, a participant can be sure to talk to the right domain by defining the domain-id on the domain connection, because we will check the topology state against this domain-id too.

Replay attacks are prevented using a max-sequencing timestamp which prevents that a message is replayed to different recipients at a later point in time.