[Command] Added LockHelper

| Q             | A
| ------------- | ---
| Doc fix?      | no
| New docs?     | yes https://github.com/symfony/symfony/pull/10475
| Applies to    | Symfony version 2.6+
| Fixed tickets | -
Too bad, it would be cool if you could pass any writeable stream, including something shared. Sorry, feature creep - maybe someday when/if the Filesystem component does more than just the local filesystem ;).