Limit initial SeedNode connections when entering the network

[tegefaulkes]

Specification

Currently there is a pretty dumb method of limiting the initial connections. We take the list of all seed nodes, sort them by distance and select the closest 3 nodes. This will limit the number of initial connections to seed nodes, but will cause problems if the 3 seed nodes selected happen to be down.

We need to use a smarter method here. Something that takes into account any failed connections. Such as concurrently attempt 3 connections until N connections are made and then proceed with the network entry.

Additional context

• Related: 287d0b0

Tasks

1. Implement a smarter method for limiting initial connections to seed nodes.