Cleanup cards v1

Removes cards V1, eek.

I've moved the old image attribution partial to be a proper component. The card page, layer and list Sass partials are not in the cards/ subdirectory because they should be re-named ASAP. 
Is [`%image-replacement`](https://github.com/lonelyplanet/rizzo/blob/master/app/assets/stylesheets/sass/extends/helpers/_image_replacement.sass#L1-L11) what you're after here?