refactor(@embark/blockchain_process): swallow errors, revise streams

[michaelsbradleyjr]

For reasons unknown, ECONNRESET errors on websocket connections to embark's blockchain proxy are not automatically handled on Windows as they are on macOS and Linux (or those errors aren't happening on those platforms, it's difficult to determine). Explicitly swallow such errors so the blockchain process doesn't crash. Prior to this PR, the crash-behavior can be reproduced on Windows by running embark blockchain and embark run in separate terminals and quitting embark run while embark blockchain is still running.

Consistently use the simples package's WsParser to process websocket traffic instead of using WsParser for requests and the ws package's Websocket.Receiver for responses.

Consistently use pump to connect parser streams instead of using pump in some places and chain in others. Drop use of cloneable (and the package dependency) since it was used previously in hopes it would fix the errors, but it's unnecessary and didn't fix them.

[michaelsbradleyjr]

This PR works together with #1166 to prevent hangs and crashes when running / stopping embark processes.

[jrainville]

Can this cause problem for other types of errors?

[michaelsbradleyjr]

Looks like I made a mistake last night when rebasing and used an older commit... dangers of develping / testing on 3 different computers at the same time. I'm going to sort that out now.

Here's what that part will look like:

if (ws) {
  server.on('upgrade', (msg, socket, head) => {
    const swallowError = (err) => {
      console.error(`Proxy: Network error '${err.message}'`);
    };
    socket.on('error', swallowError);
    proxy.upgrade(msg, socket, head);
  });
}

I checked yesterday and here's what the docs say about net.Socket's 'error' event:

Emitted when an error occurs. The 'close' event will be called directly following this event.

Since the socket will be closed, no need to destroy it manually and there's not much more we can / should do at that point other than report with console.error().

Also, the variable I had named req previously is actually an http.IncomingMessage instance. It lacks an 'error' event and its destroy() method just destroys the underlying socket (msg.socket, alias msg.connection), which is identity with the object in the socket variable, so we don't need to do anything with it.