Symfony 5 compatibility

[alexander-schranz]

Is your feature request related to a problem? Please describe.

I want to ask if there is any planned Symfony 5 compatibility?

Describe the solution you'd like

If we implement Symfony 5 compatibility. The question is if we longer want to build on top of the symfony/templating which is deprecated. So maybe I think it would be better to go with removing that dependencies and build in directly on top of twig. This would consider to create a new major release as I think there would be some bc breaks. In this case I think I would also remove any assetic integration.

[lsmith77]

I propose to deprecate this Bundle in favor of https://github.com/Sylius/SyliusThemeBundle

cc @pamil