documentation

Pull request #321: ZBX-15534-6.4-Docker upgrade

Merge in WEB/documentation from feature/ZBX-15534-6.4-D to release/6.4

* commit 'cc4a50674f2fdb8ee00d1ebaafd4c516bfefec28':
  [ZBX-15534] fixing link
  [ZBX-15534] final fixes to Docker upgrade and installation instructions
  [ZBX-15534] updated installation instructions for Docker (draft)
  [ZBX-15534] Updated Installation from containers (draft)
  ZBX-15534 updated  container upgrade
  [ZBX-15534] Updated examples
  ZBX-15534 updated container upgrade
  ZBX-15534 updated container upgrade
  [ZBX-15534] updated Upgrade from containers (draft)
  ZBX-15534 upgraded site
  ZBX-15534 Upgrading site
  ZBX-15534 upgraded from containers