p2p: backoff from discovering peers where connections have already failed

[Maddiaa0]

Overview

At the moment we attempt to dial a set of peers if we have not met our expected number of connections. E.g. Say we are at 85 peers and the target is 100, we will always attempt to dial new peers.

The problem

We attempt to dial for peers on the heartbeat interval of 1 second, and we will blindly retry to connect to peers even if we failed to connect to them beforehand.

Backoff and do not try to redial peers we have already failed to dial