Removal of some Contact attributes

Online transaction and quick link descriptipons no longer needed.
Schema.rb tidy up
Redesign of contact show page

As per design attached in pull request, various spacing and markup changes
of the contact show page.
Adding beta label to contact show page

Beta label only appears here as it was decided that the index page didn't
need to be listed as a beta.

Needs https://github.com/alphagov/slimmer/pull/64 and
https://github.com/alphagov/static/pull/381 to be displayed.