Merge React Refresh runtime and transformer

[devongovett]

This removes @parcel/runtime-react-refresh and merges its logic into @parcel/transformer-react-refresh-wrap. The initialization logic moves into an init helper function instead of being run in the runtime. This avoids mismatching versions, and mismatching logic for when refresh is applied. For example, the transformer looks at dependencies in the asset, whereas the runtime looked at the package.json only for entry assets. For bundles that have no entry assets (which is the case for all React Server Components bundles), the runtime would never be injected at all. Moving it into the transformer also deduplicates the logic into a single place instead of injecting into every bundle.