Docs/variables data (#1314)

* Replace variables.json with colors.json and update related files accordingly

* Add variables data files

* Update variables include template and all related files to use new variables data

* Fix mobile breakpoint id typo in responsivness docs page

* Fix Liquid syntax error in made-with-bulma docs page

* Update bulma sass files count in modular docs page

* Use breakpoints data in responsiveness helpers docs page

* Use breakpoints and variables data in typography helpers docs page

* Add missing page titles in docs pages front matter

docs/documentation/layout/footer.html

@@ -3,9 +3,6 @@ title: Footer
 layout: documentation
 doc-tab: layout
 doc-subtab: footer
-variables:
-- name: $footer-background-color
-  value: $background
 ---
 
 {% include subnav-layout.html %}
@@ -33,6 +30,6 @@ variables:
 
     {% include snippet.html content=footer_example horizontal=true more=true %}
 
-    {% include variables.html layout=true %}
+    {% include variables.html %}
   </div>
 </section>