[EPIC] TranslationToolsBundle compatibility with Twig v1, v2 and v3

Thanks to @atomiix and @sowbiba tests, it has been confirmed that TranslationToolsBundle is not fully compatible with Twig v2 and Twig v3 although the composer.json states so.

It also seems that it will be hard to maintain compatibility with the 3 versions of Twig, given breaking changes between v1 and v2 and v3 and v3.

If this is confirmed, we might need to have TranslationToolsBundle v4 compatible with Twig 1, and TranslationToolsBundle v5 compatible with Twig 3 and maybe 2. TranslationToolsBundle v4 would be used in PrestaShop 1.7.x until 1.7.8 and TranslationToolsBundle v5 would be used in more recent PrestaShop versions.

This means we should keep a branch 4.x open to be able to release patch versions of TranslationToolsBundle v4.

TODO

1. https://github.com/PrestaShop/TranslationToolsBundle/issues/90
2. https://github.com/PrestaShop/TranslationToolsBundle/issues/91
3. https://github.com/PrestaShop/TranslationToolsBundle/issues/92
4. https://github.com/PrestaShop/TranslationToolsBundle/issues/93

Start with composer.json and the compatibility findings linked in issues #90, #91, #92, and #93. Review the TranslationToolsBundle versioning proposal and determine whether separate 4.x and 5.x compatibility lines are required; done means the Twig compatibility plan and related TODOs are resolved.