Add a sub-menu to the shuffle playlist menu to decide how to shuffle.

[Vinzzzze]

Change the menu Shuffle playlist (mainwindow ui) to offer three shuffle modes :

• track based shuffle (the actual playlist shuffle mode)
• album based shuffle : shuffle the playlist by album and make the album played in the track number order
• grouped track shuffle : keep the grouped tracks together, other tracks and distinct track group are shuffled.

Correct what I consider as an issue : when playing a playlist with a mode shuffle grouped, the tracks are played in the order they have in the playlist. Grouped tracks must be played following the track number order.

Update mainwindow for updating the menus
Update playlist to make the ReshuffleIndices reusable for both Reshuffling indices when playing in shuffle mode and when shuffling the playlist from the menu. I left some commented code with a TODO mark for some code linked to another PR to remind me what to do when I will merge one branch in the other.
Update the playlistmanager and it's interface to handle the choice we can now make while shuffling a playlist.
Add the translations for the created menu