Synchronous fromJSON in hal

[remidewitte]

Context :

1. We are using Ketting in a Next.js application.
2. We do some data fetching using in getStaticProps, where props needs to be serializable. HalState is not as is.
3. We want to to convert a json in injected props by Next to synchronously populate the cache before rendering, so we need fromJSON to be sync (factory is async because of await response.json()).

We don't really need the changes in base-state.ts and interface.ts.

[remidewitte]

Ping @qmachard .

[remidewitte]

Hi @evert !

Do you have an opinion on this one ? Or do you prefer #472 ?

Use case is similar to what's described here : https://tanstack.com/query/v4/docs/react/guides/ssr

Cheers,
Rémi