netrc: address several netrc parser flaws

netrc: address several netrc parser flaws

- make sure that a match that returns a username also returns a
  password, that should be blank if no password is found

- fix handling of multiple logins for same host where the password/login
  order might be reversed.

- reject credentials provided in the .netrc if they contain ASCII control
  codes - if the used protocol does not support such (like HTTP and WS do)

Reported-by: Harry Sintonen
Add test 478, 479 and 480 to verify. Updated unit 1304.

Closes #15586