documentation

Pull request #2650: Feature/ZBXNEXT-9849 7.3 D

Merge in WEB/documentation from feature/ZBXNEXT-9849-7.3-D to release/7.4

* commit '7888b585457e9997220ff74f1a49ff4aeee40074':
  ZBXNEXT-9849 improvements to list style consistency and introductory sentence, deleted repeating command.
  ZBXNEXT-9849 guide improvements.
  ZBXNEXT-9849 removed a sentence, fixed lists formatting.
  ZBXNEXT-9849 addressing recommendations.
  ZBXNEXT-9849 updated a screenshot, corrected identation.
  ZBXNEXT-9849 corrected a comment block.
  ZBXNEXT-9849 moved pictures to correct folder, improved troubleshooting sections, small corrections.
  ZBXNEXT-9849 guide improvements, adding screenshots.
  ZBXNEXT-9849 guide updates.
  ZBXNEXT-9849 added info to the guide.
  ZBXNEXT-9849 initial draft of the guide.