Add ability to fork and not just upgrade

[omritoptix]

Currently we only have ability to upgrade. Assuming some changes need to happen at specific height, we would like the ability to change the state at height similar to the framework defined by osmosis here

[mtsitrin]

actually didn't saw this kind of logic on any other chains few q come in mind:

1. What taken into consideration when choosing between on-chain upgrade and hard-fork?
2. If hard-fork needed, why we need "first run logic" as in the osmosis tools?

I think this feature is very use case specific, not sure we should pursue it until a use case for it will pop up