Improved the HTML5 and Bootstrap compliance on the website views

Change-Id: I924f84521b52d2ad9ce95e8c3945857012d6a2cf
Added a link to Weblate to the Website i18n contribute page

Change-Id: I91249e904a7c1826ff93930da08679c6532aff3c
Created a helper to easily create translated elements

Change-Id: Ie9af67ecb7d700abed397dd83f3a087476526be5
Added the I18n helper to the Website plugin's AppController

Change-Id: I6a59dcb6a887732fdd91f80b02d015ca38c41559
Created a page to describe the techniques used by Mauris

Change-Id: I7810a3a242135a4c1168740857fbb31c32d4fec0