Support protocol contract V2 (Unified gateway interface)

[lumtis]

This EPIC groups issues to complete support for system contract V2 on the protocol.

• Completing the smart contracts
• Updating protocol and ZetaClient to use the contracts
• Establishing migration plan and implementing protocol features to enable migration (example: migrate ERC20Custody migration)
• Track some problems with current smart contracts to ensure new architecture fix these

### Tasks
- [ ] https://github.com/zeta-chain/protocol-contracts/issues/198
- [ ] https://github.com/zeta-chain/protocol-contracts/issues/258
- [ ] https://github.com/zeta-chain/node/issues/2552
- [ ] https://github.com/zeta-chain/node/issues/2551
- [ ] https://github.com/zeta-chain/node/issues/2348
- [ ] https://github.com/zeta-chain/node/issues/1430
- [ ] https://github.com/zeta-chain/node/issues/2745