Restrict number of onlineNodes each node keeps track of

[AdamCollins]

Current implementation will always result in the network reaching eventual full connectivity. This is fine for small networks but will be unnecessary and a bottle neck with scale.

Possible fixes:

• Add TTL to advertisements
• Add limit to size of onlineNodes

Considerations:

• The network should avoid partitioning.
• No one node should be disconnected, as this could be hard to detect.

For more explanation see documentation under _New Node Joining_