Org show page restyled

* Organization show page:
 * Thomas removed the `well` around **Contact Information** block
 * Like `postcode` and `email`, now `website` and `donation_info` disappear if the organization has no info for them
 * Dried out test suite
 * `donation_info_msg` and `organization_helper_spec.rb` deleted as we no longer use a helper method to render text in the view
 * `donation_info` and `charity_page` features with outdated assertions changed