documentation

.D........ [ZBXNEXT-7559]  SMART plugin update and template documentation update

* commit '00654ab3f470e506656a2e90b1b0902ecab11b70':
  zabbix_agent2.md changed some wording
  whatsnew604.md edited online with Bitbucket
  template_changes.md edited online with Bitbucket
  template_changes.md list of templates updated
  whatsnew604.md lis of templates updated
  [ZBXNEXT-5580] updated file system utilization tresholds in templates
  updated whatsnew604.md and template_changes.md
  updated zabbix_agent2.md