* feat(useBrainApi): add subscription creation to sdk * feat: add share brain submit handler
* refactor(MultipleBrain): separate providing and data fetching * refactor(MultipleBrain): update useBrainApi * feat(MultipleBrains): remove unnecessary data fetchings * test(useBrainApi): update unit tests
* refactor(<ExplorePage/>): add useExplore * feat(api): add useBrainApi * test(useBrainApi): add unit tests