Move stable coins of treasury for yield

Thanks to Bailey's initial idea, we are proposing to deposit 90% of the treasury stable coin into yearn.fi , minus the amount that is allocated for the Rewards Committee ($50k was approved previously),

Yearn has been sufficiently battletested for us to deposit our funds. We should use the native vaults (USDC into USDC Vaults) and try to limit exposure to USDT as there are always concerns with Tether being unbacked.