Add `codeSubstitutes` to rococo parachains (#4669)

Since the fix for https://github.com/paritytech/polkadot-sdk/issues/4559
was to add a codeSubstitute to the rococo-parachains, we should update
the chain-specs in the repo.

The json diffs are not super easy to review, so if you want to manually
check:
- Run for example `jd -o people-rococo.diff
people-rococo-from-this-branch.json people-rococo-master.json`
- Check in the resulting diff file that only `codeSubstitutes` field is
changed