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)
Can we apply background on ```<a>```?
It's less amount of markup + more semantic when we don't use empty tags.