The user can also edit the question after adding it.
The question in the poll can only be added/edited
by the user who started the poll.
The input bar will be disabled for the other users
if the question is not yet added. If the question is
added, the input bar will not be visible to the other
users.
These styles aren't great, but they're hopefully
better than none at all and inspire a follow up
commit from somebody else (so it starts to look
like a "real" feature instead of feeling completely
proof-of-concept).
A "zform" knows how to render data that follows our
schema for widget messages with form elements like
buttons and choices.
This code won't be triggered until a subsequent
server-side commit takes widget_content from
API callers such as the trivial chat bot and
creates submessages for us.