[SecurityBundle] Firewall providers building - code cleaning
Merge branch '2.3' into 2.5

* 2.3:
  [SecurityBundle] Firewall providers building - code cleaning
  [Filesystem] symlink use RealPath instead LinkTarget
  Fixed the AuthenticationProviderInterface alignment
  Fixed the proxy-manager version constraint

Conflicts:
	composer.json
	src/Symfony/Bridge/ProxyManager/composer.json