Make polls shareable to and reachable by federated cloud id

[xundeenergie]

Sharing not only via Email, let's do it also via federated cloud id

As a poll owner i want to share polls with a federated cloud id, the same as i can do with files. When i share a poll with a federated cloud id, the other user on the remote nextcloud-instance should see the poll on his nextcloud, an should be able to modify it from his own nextcloud (check, uncheck, create new options...).

Sharing via federated cloud id should also be possible for admin/owner-rights.