RIP-004: Convert MIM to FRAX & USDC

MIM as a stable is losing confidence across DeFi. At present it sits in the corner of the Rome treasury collecting dust.

This proposal seeks to authorize the DAO to swap out of MIM and into other trusted stable assets.

This proposal seeks to swap the assets into FRAX & USDC. In particular, $4.1M MIM --> $xM FRAX, $xM USDC

The DAO will use the USDC and FRAX acquired in this swap to bootstrap the FRAX Stable Swap on Moonriver.

At present there is no highly trusted stable swap on Moonriver and getting up these stable rails will offer the Moonriver ecosystem a fresh start on this front.

Additionally, we expect FXS and MOVR incentives to become available along with the base APR (6%) we will earn from fees on the pool.

Lastly, in game we will support this stable swap via a currency vendor.

The actual execution of this transaction will act as bridging out MIM from the DAO multisig on Moonriver to a DAO multisig on Ethereum. The DAO will then execute a transaction on Curve to swap into USDC & FRAX and then bridge those stables back into Moonriver and deposit into the FRAX stable swap to begin earning yield.