documentation

Pull request #2480: DEV-3947 upgraded notes (sub-issue 50).

Merge in WEB/documentation from feature/DEV-3947-7.3-D-s50a to release/7.4

* commit '2ffe42cdc03e37660c4e92918b0cec777c24cf70':
  DEV-3947 upgraded notes (sub-issue 50).
  DEV-3947 upgraded a note for RHEL (sub-issue 50).
  DEV-3947 moved part of the note to the more appropriate place (sub-issue 50).
  DEV-3947 upgraded notes (sub-issue 50).