Repulled ex-new Spice: Mtg

Sorry, my fault. I wrongly closed my old pull request for Mtg Spice. This is the new one.
Spice idea was taken from here: https://duck.co/ideas/idea/4614/lookup-a-card-from-magic-the-gathering
sourceName should be "M:tgDb" judging by the website. This URL should be the value for `sourceURL`