iroh p2p connect improvements

[ramfox]

For our initial release, we have implemented a naive iroh p2p connect command that attempts to dial the given address & fails if there are any issues.

Unfortunately, until we can get some way to have more control over the connection manager (libp2p/rust-libp2p#2828 incoming?), this command is not reliable, due mainly to ConnectionLimit errors.

Once we have more advanced access to the connection manager through the NetworkBehavior, we can examine the outgoing connections & decide whether or not we want to allow it to connect, regardless of connection limits.

---

Until then, if you need to force iroh p2p connect for some reason you can try doing the following:

• artificially high connection limit: set your connection limit in the config to an extremely large number
• removing bootstrap peers: if you are dogfooding or just know that all you want your node to do is to connect to one specific other node, you can comment out the bootstrap peers, so your node won't be flooded with connection that could potentially eat up all of the connections