documentation

Pull request #1004: feature/ZBXNEXT-8086-7.0-D: Ability to use all widgets in template dashboards (updates to Zabbix Manual).

Merge in WEB/documentation from feature/ZBXNEXT-8086-7.0-D to release/7.0

* commit 'ccd7d7c984d09e2738a99f457742a8e0350e5b58':
  [ZBXNEXT-8086] Updated info on editing widgets of the host dashboards
  [ZBXNEXT-8086] Updated "Sort entries by" parameter description
  [ZBXNEXT-8086] Fixed incorrect link to "Host availability" widget page
  [ZBXNEXT-8086] Fixed formatting mistakes (punctuation, line breaks, image sizes)
  [ZBXNEXT-8086] Ability to use all widgets in template dashboards (updates to Zabbix Manual)