[BIP-37] Allocate BAL Liquidity to Polygon & Arbitrum Multichain Bridge

Motivation

As you may recall BIP-3 allocated 40k BAL towards Ethereum<>Optimism bridge liquidity on Multichain. Since then this liquidity has seen fairly good usage. I reached out to Multichain to add Polygon & Arbitrum support to their router which is now operational - it just needs to be seeded with BAL liquidity so users can start bridging.

I think it's valuable to be able to easily transfer BAL between all of Balancer's deployments, plus this puts to work idle BAL in the Treasury as we do earn bridging fees on all of this activity. As BIP-19 begins to drive more adoption for us on Polygon & Arbitrum it is reasonable to expect an increased demand in bridging BAL between networks.

Specification

If approved, the DAO Multisig 0x10A19e7eE7d7F8a52822f6817de8ea18204F2e4f will send 40,000 BAL to the liquidity mining multisig 0xc38c5f97B34E175FFd35407fc91a937300E33860. From there, the Maxis will bridge 20,000 BAL to Polygon and 20,000 BAL to Arbitrum then supply liquidity to Multichain.