Allow a poll to be unpublished

@Berdir, what do you think about it?

I think it makes more sense to allow a poll to be unpublished similar to a regular entity/node. A closed poll should still be accessible to show the results in many/most cases.

Hi @BramDriesen,

The "published" = "status" (entity_keys) is already exists as Active(A flag indicating whether the poll is active.) Field,

this Active filed is used to open or close any poll, I guess we have to introduce new filed for open or close any poll, and will use this field to publish or unpublished any poll.

Please confirm.

Thanks
Samit K.