Creates a task that can set the owner of any contract that is `Ownable`.
It defaults to attempting to set the address of the `OVM_GasPriceOracle`
on L2. The following config options must be set:

- `CONTRACTS_RPC_URL`
- `CONTRACTS_DEPLOYER_KEY`

It can be invoked like so:

```
$ npx hardhat set-owner --owner 0x..
```

On L2 networks that do not enforce transaction fees, the
`--transaction-gas-price 0` config option may be used for
convenience.

This script also supports Ledger with the `--use-ledger` flag.
It defaults to deriving a key at the `ethers.utils.defaultPath`.