InfoDB - Wrapper class for the database The database has an
additional table for all additional information about the type of uid of the application user and the tracks_rus table, which counts
objects that have a track. It is necessary for the correct release of porridge (images and tracks), that is, track data is not deleted
if an object with this track is saved.
PlayerMode - Abstract class of player mode.
Player can work with flow (radio), track list, local track list. Every mode autoconnect to `Player.queue_changed` and
`Player.nead_changed` signals.