[Suggestion] Add the ability to extend page timeouts

[jacktan165]

We should add the ability to extend page timeouts in setup-page.js.

const setupPage = async (page, timeout) => {
  const targetURL = sanitizeURL(process.env.TARGET_URL || `http://localhost:6006`);
  const viewMode = process.env.VIEW_MODE || 'story';
  const renderedEvent = viewMode === 'docs' ? 'docsRendered' : 'storyRendered';
  const referenceURL = process.env.REFERENCE_URL && sanitizeURL(process.env.REFERENCE_URL);
  const debugPrintLimit = process.env.DEBUG_PRINT_LIMIT ? Number(process.env.DEBUG_PRINT_LIMIT) : 1000;

  if ('TARGET_URL' in process.env && !process.env.TARGET_URL) {
    console.log(`Received TARGET_URL but with a falsy value: ${process.env.TARGET_URL}, will fallback to ${targetURL} instead.`);
  }

  await page.goto(`${targetURL}iframe.html`, {
    waitUntil: 'load',
    timeout <-- add timeout option here
  }).catch(err => {

There were many times my integration tests were failing due to slow startup time, but when I increased the timeout manually in node_modules, all my tests passed.
No idea why it takes quite a long time to build storybook but it is quite annoying.

[bodograumann]

This would be great. Even better when we could set it via an environment variable or an argument to test-storybook.

I think the current suggested workarounds are to either reduce the number of parallel jobs with --maxWorker=N or run against a static storybook build.