Allow for the addresses used in the deploy script to be defined
by a JSON file at the the path defined by the `ADDRESSES` environment
variable. This makes the deploy script easy to use when it comes to
composing with the `superchain-registry`. Just set the `ADDRESSES`
env var to the path on the local filesystem that points to the
`extra/addresses/<network>/<l2>.json` file. See the
[example](https://github.com/ethereum-optimism/superchain-registry/blob/main/superchain/extra/addresses/mainnet/op.json) here.

This gives a path forward for deprecating the concept of `deployments`
in the `contracts-bedrock` package. We really only use the `deployments`
directory for getting contract addresses. We want a single source of
truth for contract addresses which is `superchain-registry`. Using this
env var allows the deploy script to easily compose with
`superchain-registry`.

`ffi` and `jq` are used instead of `vm.readFile` to break out of the
security properties that foundry uses, we do not want to need to specify
all possible directories on the filesystem as readable in the
`foundry.toml`