[Translation] added LoggableTranslator.

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #3015, #2435
| License       | MIT
| Doc PR       | symfony/symfony-docs/pull/4050
I am not such a fan of dynamic defaults as it means you get different output from ``config:dump-reference`` depending on the environment. then again I guess its the "honest" thing because if you default to false here and then overwrite the false in dev mode, then it is confusing as well.