Use interface-transport tests with a wss multiaddr

[vasco-santos]

For testing this module with a wss multiaddr we need to configure the server properly using a certificate.

const server = https.createServer({
  cert: fs.readFileSync('./test/fixtures/certificate.pem'),
  key: fs.readFileSync('./test/fixtures/key.pem')
})

ws.createListener({ server }, conn => pipe(conn, conn))

After this, and taking into consideration that we will use a self-signed certificate, we also need to provide the option rejectUnauthorized: false to the Websocket instantiation, through passing this option in the ws.dial() call.

The current version of interface-transport does not allow us to configure each test individually, which does not allow us to provide this configuration only if we are using a wss multiaddr, which is mandatory to get these multiaddr.

[vasco-santos]

In the context of #92 , I created a test using wssoutside the interface-transport suite, but we should in the future use the interface-transport for this as well

[D4nte]

Is using an https server the only way to listen on a wss multiaddr?
I am currently using libp2p-websockets to create a listening node for some custom protocols, I only use libp2p at the moment and was wondering how I can listen on a wss multiaddr. Is there any documentation I could read?