helper contracts for separating logic and data

[maraoz]

Idea from https://youtu.be/1D7BH8krdhQ?t=11m54s

Some of this is already present in Ownable.sol, but needs more thought

[come-maiz]

I think people can apply this pattern with what we have in the repo. He mentions transfer ownership, that's Ownable. He mentions transferring stuff before self destruct, https://github.com/OpenZeppelin/openzeppelin-solidity/blob/v1.9.0/contracts/lifecycle/TokenDestructible.sol shows how to do that. With these, somebody can make a contract for data and another that allows to transfer the ownership of that data.

He also mentions a generic storage. We have been experimenting with that in the labs on EternalStorage, but I'm not sure if we want to move something like that into openzeppelin.

I also don't think it would be a good idea to apply this pattern to all the contracts in openzeppelin; and most of his concerns will be solved by the upgradeability in zeppelinOS.

I'm not going to close this issue (yet), in case I'm missing some details that we would like to have in the framework.

[nventuro]

I think proxy contracts (such as ZeppelinOS's) are a more robust solution to this issue, and should advocate for those when this requirement is present.