CE-1162 WAM index page redesign implementation

! DO NOT MERGE !

See [CE-1162](https://wikia-inc.atlassian.net/browse/CE-1162)

This PR contains changes in the [WAM index page](http://wikia.com/WAM) and necessary changes in WAMService that will allow to present WAM scores for the new 7 verticals.

The work is still in progress but I would like to start a review for the changes:

@kvas-damian @Grunny @SebastianMarzjan - can you take a look at the changes? (especially SASS, JS and WAMService ones)
I'm not sure if this should be public mixin. On every call it creates base64 image string and pushes to output CSS file. We can easily create duplicates there. 
What do you think about using Extend http://sass-lang.com/guide#topic-7 ?