Add queryCache de/rehydration (#728)

* chore(hydration): set up separate hydration entry point

* feat(hydration): add support for de/rehydrating queryCaches

- Add dehydrate(queryCache, config)
- Add hydrate(queryCache, dehydratedQueries, config)
- Add useHydrate(dehydratedQueries, config)

* test(hydration): fix broken type in test

* rename scheduleTimeoutsManually to activateTimeoutsManually

* docs(hydration): add API-docs for hydration and update comparison

* docs(ssr): update ssr-docs with new approach based on de/rehydration

* remove activateTimeoutsManually

* add default shouldDehydrate

* add hydration/ReactQueryCacheProvider

* use unknown for initialData in dehydration

* rename initialQueries  and dehydratedQueries to dehydratedState

* include queryKey instead of queryHash in dehydration

* update initialQueries to dehydratedState in ssr guide docs

* remove shouldHydrate-option