[feature] Clearing song list should create new list instead

[sampie777]

We can create multiple song lists. Some people like to keep these. So the idea is to implement the following:
When a user clears the song list by using 'Delete all' mode, the song list should be kept and a new song list should be created. That way the current song list is 'cleared', but the old song list is kept in history.

When adding the first song to the songlist, the songlist's name should be auto generated from the data this song is added.