[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 | -
Some people asked in the blog post things about what happens when there are problems. For instance, is the wait for the lock release truly indefinite? Any best practice about how to deal with those situations?