Create and display links to webpack blog

[dmitriid]

Basically copying it from #327 (see comment ):

Feature request:

• update webpack README, webpack 1.x doc site with a link to the official webpack blog
• on webpack.js.org, possibly:
  • move the icons into the top header
  • add a footer with proper text links (to aid discoverability through search engines etc.)

The reason is: currently the blog is undiscoverable and a people are very surprised when they hear about it. However, it's a good source of webpack-related news.

[johnstew]

PR for this here, #700.

Added in the blog link to the top navigation only for now. The footer looks pretty balanced and wasn't sure where this should go down there. Will defer to @bebraw or @TheLarkInn on if it should be added there.

[skipjack]

Closing as #700 was merged.