RPC configurations

Bridge: https://bridge.delta.testnet.l2.quarkchain.io
Token Migration: https://migration.delta.testnet.l2.quarkchain.io
Faucet: https://qkc-l2-delta-faucet.eth.sep.web3gateway.dev
Explorer：https://explorer.delta.testnet.l2.quarkchain.io
RPC: https://rpc.delta.testnet.l2.quarkchain.io:8545