Refactor domain force delete, add "death" force delete mailer template

#268

spec/features/admin/domains/force_delete_spec.rb

@@ -0,0 +1,33 @@
+require 'rails_helper'
+
+RSpec.feature 'Force delete' do
+  context 'when domain has no force delete procedure' do
+    given!(:domain) { create(:domain_without_force_delete) }
+
+    scenario 'schedule' do
+      sign_in_to_admin_area
+
+      visit edit_admin_domain_url(domain)
+      click_link_or_button 'Force delete domain'
+
+      expect(page).to have_text('Force delete procedure has been scheduled')
+    end
+  end
+
+  context 'when domain has force delete procedure' do
+    given!(:domain) { create(:domain_without_force_delete) }
+
+    background do
+      domain.schedule_force_delete
+    end
+
+    scenario 'cancel' do
+      sign_in_to_admin_area
+
+      visit edit_admin_domain_url(domain)
+      click_link_or_button 'Cancel force delete'
+
+      expect(page).to have_text('Force delete procedure has been cancelled')
+    end
+  end
+end