Add BEAN as collateral (and slowly replace DAI)

Beanstalk (BEAN) is a decentralized credit based algorithmic stablecoin protocol that is built on Ethereum. Beanstalk uses credit instead of collateral to create price stability relative to a non-blockchain-native asset.

A stablocoin with NO-collateral needed!

Highlights:

• The first Beanstalk issues a USD stablecoin (BENA) on the Ethereum blockchain.
• Beanstalk offers a variety of passive and active opportunities for BEAN holders to earn interest directly from the protocol.
• Beanstalk does not have any collateral requirements. Beanstalk uses credit instead of collateral to create price stability relative to a non-blockchain-native asset.