Expose duration to hold artifacts as a config parameter

[bahmutov]

The collected artifacts (screenshots, videos) are stored in case of a failed test run and are kept for 1 week. We should allow the user to configure this as a parameter in the package.json

[bahmutov]

Even better: allow separate duration for success artifacts (something short, just to compare to failed ones) and another duration for failed ones (longer for debugging).

This will allow comparing success vs failure artifacts