Add admin UI for managing email subscriptions (#38741)

Co-authored-by: Claire <claire.github-309c@sitedethib.com>

app/controllers/admin/email_subscriptions_controller.rb

@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+class Admin::EmailSubscriptionsController < Admin::BaseController
+  def index
+    authorize :email_subscription, :index?
+
+    @enabled = Setting.email_subscriptions
+    @roles = UserRole.where('permissions & ? != 0', UserRole::FLAGS[:manage_email_subscriptions] | UserRole::FLAGS[:administrator])
+    @accounts = Account.local.joins(:email_subscriptions).where.associated(:email_subscriptions).includes(:user)
+  end
+
+  def disable
+    authorize :email_subscription, :disable?
+    Setting.email_subscriptions = false
+    redirect_to admin_email_subscriptions_path, notice: I18n.t('admin.email_subscriptions.disabled_msg')
+  end
+
+  def purge
+    authorize :email_subscription, :purge?
+    Admin::EmailSubscriptionsPurgeWorker.perform_async
+    redirect_to admin_email_subscriptions_path, notice: I18n.t('admin.email_subscriptions.purged_msg')
+  end
+end