`cn-quickstart` should extra localnet config (and necessary localnet files) from splice bundle

The splice bundle includes localnet config

Therefore, qs should pull this bundle (based on configured splice version), and extract the localnet config from that bundle, rather than maintaining a separate copy of that config in source in the repo.

Or, if we do want to keep a cache of that in the cn-quickstart repo for whatever reason, we should have machinery to automatically pull the latest and update the cached copy whenever the splice version is changed in cn-quickstart

https://docs.dev.sync.global/app_dev/testing/localnet.html#docker-compose-based-deployment-of-a-local-network

Start by tracing how cn-quickstart uses the configured splice version and where its localnet files are maintained. Read the linked localnet deployment documentation, then determine whether done means extracting config from the bundle or automatically refreshing a cached copy when the splice version changes.

Written by the indexing model from the issue text.