Update documentation pages to original layout

[molant]

The original layout proposed by @ststimac had a title, followed by an introduction and then the page was split in two, left side for ToC, right side for content.
Something similar to the following:

We've removed since the lorem ipsum part to address other higher priority issues but we should revisit the initial layout. What I'm proposing is:

• The introduction will be the first section of the markdown document: whatever text is between the first # and the next one (could also be ## , etc.).
• The biggest problem is the markdown rendering for that section:
  • We will at least have some inline code in some pages
  • The documentation isn't ready for this format

We will have to update /helpers/updater.js and find a way to render markdown in the description and not just the other content.

Updating the documentation should be done in webhintio/hint#225

[ststimac]

Currently the markdown file is generating two h1 elements. Hopefully we can address this when we update to the original layout.