Generate playlist preview

[balaraz]

Checklist

• [X] I've checked that there is no other issue about this feature request.
• [X] This issue contains only one feature request.
• [X] The title of this issue accurately describes the feature request.

Feature description

You can make several preview generation options:

• Image of the first song
• Images of the first few songs
• Images of selected songs. Available only in the "per playlist" mode.
• Unique images of the first few songs. Checks if the songs do not belong to the same album. If they do, this image is skipped.

You can make this setting common to all playlists or individual for each playlist.

Why do you want this feature?

It is very inconvenient to see the same images. It is less informative.

Additional information

No response