feat!: add design tokens support (#2187)

BREAKING CHANGE: Pre-design-tokens theming is no longer supported.

Co-authored-by: Diana Olarte <diana.olarte@edunext.co>

.env

@@ -45,3 +45,5 @@ ENABLE_CHECKLIST_QUALITY=''
 ENABLE_GRADING_METHOD_IN_PROBLEMS=false
 # "Multi-level" blocks are unsupported in libraries
 LIBRARY_UNSUPPORTED_BLOCKS="conditional,step-builder,problem-builder"
+# Fallback in local style files
+PARAGON_THEME_URLS={}