documentation

Pull request #185: Feature/ZBX-21042 6.0 D

Merge in WEB/documentation from feature/ZBX-21042-6.0-D to release/6.0

* commit '47380d8598e036ba2c92563cc69baef75af2d929':
  removed unnesessary empty directories (inherited from DokuWiki)
  [ZBX-21042] removed selinux.md page
  [ZBX-21042] added SELinux package description