p2p: more ergonomic errors

[bajtos]

At the moment, errors reported by libp2p are translated to vanilla JavaScript errors with no additional properties. This makes it difficult to implement custom handling for specific kinds of errors (e.g. timeouts).

Example error:

Identify protocol failed: Error: cannot dial remote peer: Timeout while waiting for a response
    at async Object.requestProtocol (ext:zinnia_libp2p/01_peer.js:14:27)
    at async probe (file:///Users/bajtos/src/zinnia/mod-peer-checker/peer-checker.js:29:22)
    at async file:///Users/bajtos/src/zinnia/mod-peer-checker/peer-checker.js:104:33

I am proposing to improve the layer converting rust-libp2p errors into JavaScript errors to produce machine-readable error objects.

For example:

• Change the error name to something like PeerError
• Add a code property set to a unique string that can be used to differentiate errors. For example map OutboundFailure::Timeout to { code: "OUTBOUND_TIMEOUT" }