Blind test feature

Create a feature to run blind test between a community of users:

• One person is the one handling the playlist (that could be created using a flow from an artist or a music type)
• The other users connect to the blind test and have to choose the artist (and eventually the song name) from an autocomplete drop down menus
• We could also add a `Badge` feature to tag the users (for example a badge when winning 10 blind tests, or if we find an artist in less than 5 seconds, etc.)