[API] Add notification endpoint (#9488)

* [API] Add notification endpoints

 * add func GetNotifications(opts FindNotificationOptions)
 * add func (n *Notification) APIFormat()
 * add func (nl NotificationList) APIFormat()
 * add func (n *Notification) APIURL()
 * add func (nl NotificationList) APIFormat()
 * add LoadAttributes functions (loadRepo, loadIssue, loadComment, loadUser)
 * add func (c *Comment) APIURL()
 * add func (issue *Issue) GetLastComment()
 * add endpoint GET /notifications
 * add endpoint PUT /notifications
 * add endpoint GET /repos/{owner}/{repo}/notifications
 * add endpoint PUT /repos/{owner}/{repo}/notifications
 * add endpoint GET /notifications/threads/{id}
 * add endpoint PATCH /notifications/threads/{id}

* Add TEST

* code format

* code format

routers/api/v1/swagger/notify.go

@@ -0,0 +1,23 @@
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package swagger
+
+import (
+	api "code.gitea.io/gitea/modules/structs"
+)
+
+// NotificationThread
+// swagger:response NotificationThread
+type swaggerNotificationThread struct {
+	// in:body
+	Body api.NotificationThread `json:"body"`
+}
+
+// NotificationThreadList
+// swagger:response NotificationThreadList
+type swaggerNotificationThreadList struct {
+	// in:body
+	Body []api.NotificationThread `json:"body"`
+}