Made Twig support optional via config

[d-kochnov-optimus]

Looks like the Twig support feature can't be disabled at all.

At the same time the Twig bundle is not required in the composer.json.

So, the attempt to use the EncryptBundle on apps without Twig bundle leads to the Attempted to load class "Twig_Extension" from the global namespace. error.

Can the Twig support feature be configurable? At lest in supported vesions.