Added Lines Before Namespace Fixers

NoBlankLinesBeforeNamespaceFixer is a contrib level fixer, and OneBlankLinesBeforeNamespaceFixer is a symfony level fixer.
there should also be a test without newlines like shown in https://github.com/FriendsOfPHP/PHP-CS-Fixer/pull/879/files#diff-2c585ece9a0f211c378faadfc83092cbR58