Prevent users from adding tracks that have already been played

[TheDom42]

Hey there,
another suggestion I would like to make would be an option in the admin panel to prevent users from adding tracks to the queue that have already been played during the party. This is partially related to #102 and #129 but I think it would be a great addition to the vote spamming feature (so that songs are not played over and over again because a small group of people add and vote for it after it has already been played before).