Dislike and a bare /feedback open the Session's feedback dialog, which
collects one of seven fixed categories and an optional description and
records through the messageFeedback put or the new sessionFeedback
Remote; Like records at once. A recorded rating shows the filled glyph
and every submission is acknowledged by a toast. feedback/record and
MessageFeedbackItem carry the optional category; the note popover, its
layout scenario, and the clearNote/clear verbs are removed. ui-commands
gains the action command kind the /feedback decoration runs as.
Closes#3515
creatixchu