Remove JavaScript in navbar and include logout

Signed-off-by: Tobias Eidelpes <tobias@eidelpes.info>

app/helpers/application_helper.rb

@@ -1,18 +1,4 @@
 module ApplicationHelper
-  # Contains the complete navbar
-  def nav_bar
-    content_tag(:div, class: 'topnav', id: 'topnav') do
-      yield
-    end
-  end
-
-  # Defines individual links in the navbar. To be used inside nav_bar
-  def nav_link(text, path)
-    # Sets active class on the link corresponding to the page being viewed
-    options = current_page?(path) ? { class: 'active' } : {}
-    link_to text, path, options
-  end
-
   # Used to render svg image files
   def show_svg(path)
     File.open("app/assets/images/#{path}", 'rb') do |file|