documentation

Pull request #3304: feature/ZBXNEXT-9920-7.5-D-v2

Merge in WEB/documentation from feature/ZBXNEXT-9920-7.5-D-v2 to release/8.0

* commit '3e95977a5596135fb194f53550529abaa9f802bc':
  [ZBXNEXT-9920] clarified the scope of font use in themes
  [ZBXNEXT-9920] new and embedded fonts