Add administrative webhooks (#18510)

* Add administrative webhooks

* Fix error when webhook is deleted before delivery worker runs

app/controllers/admin/webhooks_controller.rb

@@ -0,0 +1,77 @@
+# frozen_string_literal: true
+
+module Admin
+  class WebhooksController < BaseController
+    before_action :set_webhook, except: [:index, :new, :create]
+
+    def index
+      authorize :webhook, :index?
+
+      @webhooks = Webhook.page(params[:page])
+    end
+
+    def new
+      authorize :webhook, :create?
+
+      @webhook = Webhook.new
+    end
+
+    def create
+      authorize :webhook, :create?
+
+      @webhook = Webhook.new(resource_params)
+
+      if @webhook.save
+        redirect_to admin_webhook_path(@webhook)
+      else
+        render :new
+      end
+    end
+
+    def show
+      authorize @webhook, :show?
+    end
+
+    def edit
+      authorize @webhook, :update?
+    end
+
+    def update
+      authorize @webhook, :update?
+
+      if @webhook.update(resource_params)
+        redirect_to admin_webhook_path(@webhook)
+      else
+        render :show
+      end
+    end
+
+    def enable
+      authorize @webhook, :enable?
+      @webhook.enable!
+      redirect_to admin_webhook_path(@webhook)
+    end
+
+    def disable
+      authorize @webhook, :disable?
+      @webhook.disable!
+      redirect_to admin_webhook_path(@webhook)
+    end
+
+    def destroy
+      authorize @webhook, :destroy?
+      @webhook.destroy!
+      redirect_to admin_webhooks_path
+    end
+
+    private
+
+    def set_webhook
+      @webhook = Webhook.find(params[:id])
+    end
+
+    def resource_params
+      params.require(:webhook).permit(:url, events: [])
+    end
+  end
+end