Alternative/sidegrade suggestions and migration of downvoted relations

[Dankirk]

Related cards should have a third category (in addition to superior/inferior) for alternatives/sidegrades, that are somewhat similiar, but not strictly better or worse.

Users have added some suggestions as superior, that other users don't agree with and thus downvote them. In some cases the suggested cards are actually more of a sidegrade, so we should provide a proper way to list these cards.

When this feature is implemented, all downvoted suggestions should be re-evaluated if they fit this new category. This could be done with users help via Help Voting page. The page could have various tabs(?) how to help improve the database, one being the current one, other could be listing downvotes card relations and suggesting moving it to sidegrades instead. This should not be done with a single opinion however.

Lastly, we should provide a way to remove those downvoted relations, that don't fit to the alternative category.