Exclusion of uninteresting lands in key cards in /api/archetypes2 is a bit of a hack

[bakert]

What is decksite allowed to know about cards? Anything? So why not actually say "no cards with ci>1 and no basics". That reads a lot like a search which I'm semireluctant to do all over the place in decksite but we should figure out (a) is that allowed and (b) bring _legal_cards into line with whatever we decide and then either use search in a bunch of places or use whatever we decide is the better interface in a bunch of places.