Improvements for polls in forum

[Lyra2108]

The polls are hard to use. The following points could be improved:

• [ ] Show at least a warning if the user tries to publish a topic with an unpublished poll
• [ ] Ignore empty fields from a poll or allow to remove added poll fields afterwards
• [ ] Allow to set a maximum number of votes for a multiple choice vote
• [ ] Start the poll when the topic is published, not earlier

[Vejvej]

I want to add one point here:

• Start the poll when the topic is published, not earlier.

[Lyra2108]

Thanks I will add that

[Vejvej]

I found another issue, while creating another set of polls:

• Allow creators of polls to toggle multiple selections after adding a poll

Edit: second point is already covered. Sorry for that!