Add a11y results

[housseindjirdeh]

As suggested: https://twitter.com/inkpixelspaper/status/942901268305055744

I think this is a great idea :)

Throwing out some suggestions:

• Should we have Accessibility Score for each implementation with their LH a11y scores?
• Should we keep it general and include a bit on a11y at the very beginning of the site?
• Are there any other a11y mentions we should include?

CC @addyosmani

[addyosmani]

One idea we briefly talked about was maybe trying to add in all of the scores. @housseindjirdeh might take a look at this.