Epic: Sway core contracts production-ready

[tkporter]

Mailbox:

• https://github.com/hyperlane-xyz/fuel-contracts/issues/10
• https://github.com/hyperlane-xyz/fuel-contracts/issues/11
• https://github.com/hyperlane-xyz/fuel-contracts/issues/2
• https://github.com/hyperlane-xyz/fuel-contracts/issues/3
• https://github.com/hyperlane-xyz/fuel-contracts/issues/4
• https://github.com/hyperlane-xyz/fuel-contracts/issues/5
• https://github.com/hyperlane-xyz/fuel-contracts/issues/6 (<- will be fixed by #52)
• https://github.com/hyperlane-xyz/fuel-contracts/issues/24
• https://github.com/hyperlane-xyz/fuel-contracts/issues/58

Interchain gas:

• https://github.com/hyperlane-xyz/fuel-contracts/issues/8
• https://github.com/hyperlane-xyz/fuel-contracts/issues/44
• https://github.com/hyperlane-xyz/fuel-contracts/issues/51

MultisigIsm:

• https://github.com/hyperlane-xyz/fuel-contracts/issues/7
• https://github.com/hyperlane-xyz/fuel-contracts/issues/21
• https://github.com/hyperlane-xyz/fuel-contracts/issues/29

ValidatorAnnounce:

• https://github.com/hyperlane-xyz/fuel-contracts/issues/53

Misc:

• https://github.com/hyperlane-xyz/fuel-contracts/issues/22
• https://github.com/hyperlane-xyz/fuel-contracts/issues/67
• https://github.com/hyperlane-xyz/fuel-contracts/issues/14
• https://github.com/hyperlane-xyz/fuel-contracts/issues/54
• https://github.com/hyperlane-xyz/fuel-contracts/issues/66
• https://github.com/hyperlane-xyz/fuel-contracts/issues/76
• https://github.com/hyperlane-xyz/fuel-contracts/issues/82