Open meetings, no need for account or invite.

[aslakhol]

This is different from #2 in the sense that we would need temporary profiles for this.

Add possibility of creating meetings and votations that are open to everyone with the url /meeting/:meetingId or /meeting/:meetingId/votation/:votationId.

We would then have to generate temporary users and/or participants to be used for voting, as well as (possibly) finding a way to avoid double-registration and double-voting.
It would also require that the administrator can generate a QR-code for that url.