Introduced the CanDeleteConfirmableCommand class.
Implemented the Result property of

the CanDeleteConfirmableCommand class.
Introduced the read-only properties of CanDeleteConfirmableCommand.
Implemented the Exeucte(User) method of CanDeleteConfirmableCommand.
Implemented the Exeucte(Article) method of

CanDeleteConfirmableCommand.
Implemented the Execute(Bookmark) method of

CanDeleteConfirmableCommand.
Implemented the Execute(Keyword) method of

CanDeleteConfirmableCommand.