Make repo migration cancelable and fix various bugs (#24605)

Replace #12917

Close #24601
Close #12845


![image](https://github.com/go-gitea/gitea/assets/2114189/39378118-064d-40fb-8396-4579ebf33917)


![image](https://github.com/go-gitea/gitea/assets/2114189/faf37418-191c-46a6-90a8-353141e00e2d)


![image](https://github.com/go-gitea/gitea/assets/2114189/fdc8ee4d-125f-4737-9990-89bcdf9eb388)


![image](https://github.com/go-gitea/gitea/assets/2114189/9a3bd2c2-fe20-4011-81f0-990ed869d139)

---------

Co-authored-by: Yarden Shoham <git@yardenshoham.com>
Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: Giteabot <teabot@gitea.io>

services/task/task.go

@@ -95,7 +95,7 @@ func CreateMigrateTask(doer, u *user_model.User, opts base.MigrateOptions) (*adm
 		DoerID:         doer.ID,
 		OwnerID:        u.ID,
 		Type:           structs.TaskTypeMigrateRepo,
-		Status:         structs.TaskStatusQueue,
+		Status:         structs.TaskStatusQueued,
 		PayloadContent: string(bs),
 	}