* Extend notifications API and return pinned notifications in notifications list

Signed-off-by: Andrew Thornton <art27@cantab.net>

* fix swagger

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Fix swagger again

Signed-off-by: Andrew Thornton <art27@cantab.net>

* fix test

Signed-off-by: Andrew Thornton <art27@cantab.net>

* remove spurious debugs

* as per @6543

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Update models/notification.go

* as per @6543

Signed-off-by: Andrew Thornton <art27@cantab.net>

Co-authored-by: techknowlogick <techknowlogick@gitea.io>

* BEAKING: check return status based on struct not httpStatus

* update Tests

* CI.restart()

* introduce GET /notifications/new

* add TEST

* use Sprintf instead of path.Join

* Error more verbose

* return number of notifications if unreaded exist

* 200 http status for available notifications

* [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