Spaceless is deprecated on twig

Please review the MR.

Equivalency to spaceless is rather heavy handed to achieve. Basically there are two preconditions:

1. There can't be any markup passed in via variables (I think we meet this criteria here!)
2. Every {%, %}, {{, }}, etc... have to be converted to use whitespace control operators (i.e. {{-, -}}

I think we'll still need the second point to apply here, but I'm still rather critical of the upstream decision to remove spaceless without a 100% solid replacement (see #1) ☹️.