base: footer modularity improvement

• Removing styles on the <footer>. It's a generic element that may be used at more than one place, like <p> or <address>. http://www.whatwg.org/specs/web-apps/current-work/#the-footer-element

• Adding blocks in the footer template so one can reuse the content without having to keep the outter structure.

• Removing inline style.

Signed-off-by: Yoan Blanc <yoan.blanc@cern.ch>