documentation

[DEV-929] Updated API: Dashboard widgets fields

Merge in WEB/documentation from feature/DEV-929-6.4-D-API to release/6.4

* commit '470fd141f20ceb723c0f2301548bda5b3b696be7': (57 commits)
  [DEV-929] Updated time string formatting
  [DEV-929] Updated fields, example (svggraph)
  [DEV-929] Updated punctuation
  [DEV-929] Updated links to dashboard.create/.update
  [DEV-929] Updates to svggraph related to ZBXNEXT-5491
  [DEV-929] Updated "Request:" header, removed "auth" from JSONs
  [DEV-929] Renamed directory "widgets" to "widget_fields"
  [DEV-929] Updated broken links, added info about time zones
  [DEV-929] Renamed "widgets.md" to "widget_fields.md", updated links
  [DEV-929] Moved noteclassic's before the tables
  [DEV-929] Updated widget examples
  [DEV-929] Updated links after structure update
  [DEV-929] Updated section structure
  [DEV-929] Updated formatting
  [DEV-929] Updated formatting
  [DEV-929] Updated structure (graph, item, tophosts)
  [DEV-929] Updated parameters, formulations, etc. formatting
  [ZBXNEXT-4714] Updated "Action log" page and dashboard widget field object table
  [DEV-929] Updated "Item" param info for "Clock" widget
  [DEV-929] Updated formatting
  ...