[Twig] Decouple Twig commands from the Famework

I want to use the command `twig:lint` in a Silex project. 

In this PR, I've moved the class `Symfony\Bundle\TwigBundle\Command\LintCommand` to `Symfony\Bridge\Twig\Command\LintCommand` and removed dependency to the `ContainerAwareCommand`.

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | yes (renamed class)
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | https://github.com/symfony/symfony/pull/9818#issuecomment-30961360
| License       | MIT
| Doc PR        | n/a

 - [ ] Move command `twig:debug` once merged.
 - [ ]