Make peer-info protocol optional.

[shamil-gadelshin]

This PR sets peer-info protocol optional for bootstrap-node. We opted for a simpler design of peer-info protocol and didn't implement requesting cuckoo-filter from farmers. We push cuckoo-filter unconditionally to new connections and it's not suitable for bootstrap nodes. Bootstrap-node will receive thousands of cuckoo-filters from bootstrapping farmers which is unnecessary and could lead to a choke point.

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[nazar-pc]

In this case should we probably rename PeerInfo into FarmerInfo and simplify it to only work for farmers? We can always introduce a new protocol later.

[shamil-gadelshin]

In this case should we probably rename PeerInfo into FarmerInfo and simplify it to only work for farmers? We can always introduce a new protocol later.

I understand your viewpoint, however, I'd like to keep it at least until #1681
I'd like to try using peer-info to clean up unnecessary records from Kademlia DHT.

The proper solution of the original problem would be to reconsider peer-info design and implement three protocol phases (send, receive, send/receive extra-data) instead of two phases like now. And this PR is a shortcut.