documentation

Pull request #1587: feature/ZBXNEXT-8851-6.0-D: Updated pages.

Merge in WEB/documentation from feature/ZBXNEXT-8851-6.0-D to release/6.0

* commit 'bad5fc4f6fe9d60b7daa67a83205fcd91aca711e':
  [ZBXNEXT-8851] Improved IDs
  [ZBXNEXT-8851] Updated what's new
  [ZBXNEXT-8851] Updated PHP support