Insert PDFs in the documentation section decidim.org

[JuanLinaresLanzman]

Attached documents we use in the print version to explain the project. This documents should stay in the Documentation section ;-) (in the future the will be available editable documents)

Decidim.org (aka Decidim project)
Decidim_Org_cast_final.pdf
Decidim_Org_cat_final.pdf
Decidim_Org_eng_final.pdf

Decidim.barcelona

Decidim_bcn_cast_final.pdf
Decidim_bcn_cat_final.pdf
Decidim_bcn_eng_final.pdf

[andreslucena]

@gmarpons could you review this?
@JuanLinaresLanzman do we have this PDFs on an editable open format (ie SVG)?