Deprecate the inline feature

[yannickl88]

With the new release of twig, the inline feature has been even more unstable than before. We also had issues before that sometimes the inline did not work correctly and opted to use a 'workaround' to use the normal behavior.

Moreover, the inline feature is not complete. It does not parse twig correctly since variables cannot be replaces. This can cause a lot of confusion for new people working with it.

I propose to deprecate the inline feature and possible remove it in future releases.