Write a design doc for prepare cheatcode

[cptartur]

Create a design document for prepare cheatcode or alternative solution.

[cptartur]

We should write a design doc for this first

[cptartur]

Usecases for having the prepare cheatcode or equivalent:

• knowing the address of the contract so it can be pranked - pranking the constructor
• tests that somehow depend on knowing the contract address

In my opinion the current flow with just declare and deploy provides a nice UX and makes sense for most starknet developers - on real network you also have to first declare then deploy.

I'd avoid requiring the user to do prepare between these steps - this is how it was done in protostar. I think we should provide a way of precalulcating the address in case the user needs it, but without enforcing this calculation to do any kind of deployment.

What's problematic is for this precalculation to work, addresses would have to be deterministic: This is possible, but would then limit the user to only having one instance of a given contract. Perhaps this could be solved by using some kind of internal "counter" that would be incremented on every deployment and used as a salt for contract address. This way the address would could be precalculated without requiring the user to do so before every deployment.