documentation

Pull request #3277: Feature/ZBX-16777 7.4 D

Merge in WEB/documentation from feature/ZBX-16777-7.4-D to release/7.4

* commit '3bf7e6c9013de0b9968f70adf319f2a261f717a8':
  ZBX-16777 updated the instructions. Removed redundant sections.
  ZBX-16777 formatting, removed redundant symbols.
  ZBX-16777 changed an ampersand to a word,
  ZBX-16777 fixed a comment block.
  ZBX-16777 added instructions.
  ZBX-16777 initial draft.
  ZBX-16777 formatting.