Define and implement a communication protocol format

[matjazv]

Description

• Define generic and efficient message protocol.
• It must be in a binary format.
• Check what kind of messages are required.
• Defining envelope for the message.
• Implement/update unittests.

Acceptance Criteria

• Messages according to a defined protocol are sent over a network.
• All new code is unit tested.

Additional Information

• Publish(topic: string, data: []byte) and RegisterEventHandler need to be implemented
• Above those 2 functions need to be connected to the pubsub
• We need a method to create new topic in gossipsub