Refactor exports controller (#1567)

* Add basic coverage for settings/exports controller

* Remove unused @account variable from settings/exports controller

* Add coverage for download export actions

* Remove deprecated `render :text` in favor of `send_data` for csv downloads

* Add model to handle exports

* Use Export class in settings/exports controller

* Simplify settings/exports controller methods

* Move settings/export to more restful routes

app/controllers/settings/exports/blocked_accounts_controller.rb

@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+module Settings
+  module Exports
+    class BlockedAccountsController < ApplicationController
+      before_action :authenticate_user!
+
+      def index
+        export_data = Export.new(current_account.blocking).to_csv
+
+        respond_to do |format|
+          format.csv { send_data export_data, filename: 'blocking.csv' }
+        end
+      end
+    end
+  end
+end