Fixes bug in category#index view and adds tests

There is a bug in the category#index view since it is expecting an
article object to exist. It seems it was intended to only display
categories with published articles so I added the code needed for that
(and tests). I also moved dotenv-rails in the Gemfile so that it is
included in the production env.
removed logic from article_type.html.erb
removed logic from articles/index/html.erb
added Category::with_published_articles, called in controllers
pulled db logic out of home/category partial
removed regex and split calls from quick_answers and web_services views
removed call to User in admin templates
added @user to web_services and quick_answers admin controllers
removed unused loop from _articles_sidebar.html.erb
brought .limit back in _category
use FG syntax methods in articles_controller spec
created format_article_type(article_type) helper
created phone_number_from_article helper
created article_content_form(article, form)
Merge branch 'logic_out_of_templates' into dev