Implement production services

[negamaxi]

Services affected:

• getAlbumPreviewsByQuery
• getAlbumPreviewsFeed
• getTrackPreviewsByAlbumIds
• submitAlbumCandidate

What need to be done:

• implement a ServiceWorker / WebWorker that will encapsulate operations with IndexedDB and IPFS (SW not that easy in CRA https://karannagupta.com/using-custom-workbox-service-workers-with-create-react-app; WW ceurrently impossible AT ALL WIP: Add support for WebWorker with worker-loader facebook/create-react-app#5886)
  • implement a communication layer between main process and ServiceWorker
• refactor service layer to use event-based architecture instead of a promise-based (?)