[Arbitrum][LlamalendV1 Housekeeping] Set loan_discount to 50% on 16 LLv1 controllers; replace monetary policy on a total of 16 markets (FXN, ARB, IBTC to SemiLog MP ~0% APR; 13 idle (WBTC, 2× gmUSDC, ARB, FXN, CRV, IBTC, 2× tBTC, 3× stXAI, EYWA) to a si...