feat(script): add deployment script for new `StakeManager`s

[0x-r4bbit]

This is needed to deploy individual new StakeManager instances in both, production environment and testing.

The script can be used as follows:

Within tests, to get a new StakeManager instance that has a reference to an older StakeManager instance, run:

function setUp() public virtual override {
    super.setUp();
    DeployMigrationStakeManager deployment = new DeployMigrationStakeManager(address(stakeManager), stakeToken);
    newStakeManager = deployment.run();
}

Where address(stakeManager) is the address of the current StakeManager and stakeToken is the address of the stake token.

To deploy a new instance from the CLI using forge, one can make use of the PREV_STAKE_MANAGER and STAKE_TOKEN_ADDRESS environment variables like this:

$ PREV_STAKE_MANAGER=0x123 STAKE_TOKEN_ADDRES=0x456 forge script script/DeployMigrationStakeManager.s.sol

The script will revert when STAKE_TOKEN_ADDRESS is address(0).

Closes #71

Checklist

Ensure you completed all of the steps below before submitting your pull request:

• [ ] Added natspec comments?
• [ ] Ran forge snapshot?
• [ ] Ran pnpm gas-report?
• [x] Ran pnpm lint?
• [x] Ran forge test?
• [ ] Ran pnpm verify?