documentation

Pull request #570: [ZBXNEXT-4714] Updated filter options for Action log.

Merge in WEB/documentation from feature/ZBXNEXT-4714-6.4-D to release/6.4

* commit '1f67650af0da14164a3f381a5e7dbfcaa751bc8a':
  [ZBXNEXT-4714] Updated "Export to CSV" button description
  [ZBXNEXT-4714] Updated formatting (minor), "What's new" update placement
  [ZBXNEXT-4714] Updated "What's new", both "Action log" pages
  [ZBXNEXT-4714] Updated "What's new" and "Action log" page
  [ZBXNEXT-4714] Updated "What's new" and "Action log" page
  [ZBXNEXT-4714] Updated "Action log" page (Export to CSV)
  [ZBXNEXT-4714] Updated "Using filter" in "Action log" page
  [ZBXNEXT-4714] Updated formatting in "Action log" page
  [ZBXNEXT-4714] Updated "Overview" in "Action log" page
  [ZBXNEXT-4714] Updated image in "Action log" page
  [ZBXNEXT-4714] Updated "Overview" in "Action log" widget page
  [ZBXNEXT-4714] Updated params in "Action log" widget page
  [ZBXNEXT-4714] Updated image in "Action log" widget page