Auth Ether Faucet to manage refunds

[alcueca]

Using an auth Ether faucet, we can pool small amounts of Ether at a time to deal with refunds, this will mean:

• Less risk, since only a certain amount of Ether will be stored in the faucet at a time.
• Less work, since any developer will be able to issue refunds.
• More accountability, since the transactions from the faucet will be a log of all refunds.