[HttpFoundation] Officialize the 308 redirect RFC
[HttpFoundation] Basic auth in url is broken when using PHP CGI/FPM

Request#getUser() and Request#getPassword() introduced in
aecfd0a8917370edd237120352749141ffa85362 do not handle the lack of
PHP_AUTH_USER and PHP_AUTH_PW in $this->server when using PHP-FPM. Use
$this->headers instead.
Furthermore, the test of empty password now expects an empty string
instead of NULL according to a450d002f253e32e77d5c2bd3e490435c68a8c09.
Merge branch '2.3' into 2.4

* 2.3:
  Minor doc fix.
  Simplified the way to update PHPUnit to the latest version
  [Process] Minor README update
  [HttpFoundation] Basic auth in url is broken when using PHP CGI/FPM
  Fixed a html error "Element ul is not closed" in logger.html.twig
  [HttpFoundation] Officialize the 308 redirect RFC
  issue #10808 crawler test
  Empty select with attribute name="foo[]" bug fix
  Fixed contextually wrong translation