Added Copy as Credentials on Networks Tab

[halil07]

Added new feature. Network tab copy with Credentials for each request 'Copy as Credentials'

[JoelEinbinder]

Thanks for the patch! Unfortunately, we aren't set up to accept PRs on github. DevTools code lives in Chromium, under third_party/blink/renderer/devtools. See https://chromium.googlesource.com/chromium/src/+/master/docs/contributing.md for how to contribute, although you can safely ignore all the stuff about compiling if you only want to work on the DevTools front end.

You can add me (einbinder@chromium.org) as a reviewer once you get a patch set up.