Add List of Preconstructed Decks

[starryknight64]

From https://en.wikipedia.org/wiki/List_of_Magic:_The_Gathering_theme_decks

[fenhl]

See also taw/magic-preconstructed-decks. Since this data is not available on gatherer, this would have to be an extension.

[ZeldaZach]

Would be an extension to V4, which we can discuss in the near future on that repo

[starryknight64]

V4? What's that?

[tooomm]

With the issue beeing opened there, this can be closed then I guess?

@starryknight64 v4 is a rewrite of mtgjson which will be the new code to create the files soon.