feat(queryObserver): add isInitialLoading derived flag (#4244)

* feat(queryObserver): add isInitialLoading derived flag

this flag describes isLoading && isFetching and can be used to show a loading spinner for lazy or disabled queries

* chore(ci): fix caching

apparently, v3 has a fix: https://github.com/actions/setup-node/issues/543

* chore(ci): properly fix token issue

as described here: https://stackoverflow.com/questions/52015748/npm-failed-to-replace-env-in-config-npm-token

he extra warn output made the caching fail

* chore: fix bundlewatch glob

* docs: add a section about isInitialLoading to the migration guide