Ampache: Some refactoring
Ampache: Some refactoring

- Split handshake logic to multiple functions

- Remove an obsolete helper function `allTracksPlaylistAsArray`

- Make all internal helper functions `private` while the API methods
  remain `protected`. This makes no practical difference as the class is
  not intended for inheritance, but it helps in separating these two
  groups on the IDE outline view.

owncloud/music,paulijar/music,owncloud/music,paulijar/music,owncloud/music,paulijar/music,paulijar/music,owncloud/music,paulijar/music,owncloud/music