Remove PDF generation and make HTML one printable

app/controllers/contestants_controller.rb

@@ -131,13 +131,8 @@ class ContestantsController < ApplicationController
     @contestants = @contest.contestants.sort_by { |contestant| contestant.name }
     @nonav = true
 
-    FerrumPdf.configure do |config|
-      config.process_timeout = 20
-    end
-
     respond_to do |format|
-      format.html
-      format.pdf { render ferrum_pdf: {}, disposition: :inline, filename: "#{@contest.friendly_id}_qrcodes.pdf", layout: "blank" }
+      format.html { render layout: "blank" }
     end
   end