Migrate the network specific config in the `OptimismPortal`
from being `immutable` values into storage. This allows for
a single implementation to be used for all proxies in the
network.

As seen in the storage layout, no storage values are modified.
Only new storage values are added. This is very important for
ensuring the integrity of storage in the contract.

The deployment complexity is reduced by removing all constructor
values and setting all config in the `initialize` function.
The sentinel contract should use all null values for its fields
so that it is not confused as the contract for an actual network.

The bindings are regnerated. A follow up commit will bump the
minor semver version in the `OptimismPortal`