Allow DAO to become an event organiser

[makoto]

Problem

Currently, the event organiser is the one centralised entity to decide who to check-in/out so there is a rug-pull risk. Also, there is a risk of losing funds if organisers don't add extra admin and the person loses the private key of his/her address.

For these reasons, Kickback is not suitable for staking too high an amount.

Solutions.

• Allow Gnosis Safe or MolochDAO to take over admin ownership.
• Need at least x number of signatures to finalise the event.

Discussion point.

• Probably this makes UI quite complex so make this feature optional for only high stake events.