Add HTTPS upstream proxy support with option to ignore proxy cert errors

[patrickkfkan]

As title. E.g.:

const server = new Server({
  prepareRequestFunction: () => ({
    upstreamProxyUrl: 'https://user:pass@myproxy:8080',
    ignoreUpstreamProxyCertificate: true  // Useful for self-signed cert
  })
}).listen();

Anonymize:

anonymizeProxy({
  url: 'https://user:pass@myproxy:8080',
  ignoreProxyCertificate: true,
}).then((anonymizedURL) => {
  console.log(`Anonymized URL: ${anonymizedURL}`);
});

Create tunnel:

createTunnel(
  'https://user:pass@myproxy:8080',
  targetHost,
  { ignoreProxyCertificate: true }
).then((url) => {
  console.log('Tunnel endpoint:', url);
});

[jirimoravcik]

Hi @patrickkfkan,
thank you for your contribution!
the unit tests are sadly failing, would you be willing to take a look at that?

Thank you

[patrickkfkan]

Hello! I missed the part where options can be undefined as the type definition for createTunnel() didn't reflect this. I've fixed this in the PR so unit tests should pass now. Could you please check again? Thanks!

[jirimoravcik]

Hey, thanks for the fix. I noticed the lint is failing. Could you please rebase your PR on top of the current master branch? Thanks

[patrickkfkan]

Done.

[jirimoravcik]

Hey, I'm almost ready to merge this PR, just a few small nits. Could you please take a look at them? Thanks

[jirimoravcik]

Could you please do something with an array ['http:', 'https:'] and not in?

[patrickkfkan]

Done.

[jirimoravcik]

This feature has landed in v2.5.8. @patrickkfkan thank you again for your contribution!