Genesis with better support for ipc enabled and ipc disabled use cases

[cryptoAtwill]

Genesis should handle ipc enabled and disabled better. Currently the implementation also assumes ipc is enabled and requires artifacts in Hardhat, a proper refactor is needed to handle disabled ipc properly.

[raulk]

This makes sense. You imagine not deploying the gateway and registry contracts if the network is standalone? Is Fendermint capable of detecting this and stop producing checkpoints, prevent messages being sent, etc.? IUC, that's not the case?

Another way to look at this is that we eventually want to support subnet attachment, detachment, and migration. So ideally we should be able to enable and disable this functionality at runtime, for a truly dynamic environment.