[major] Support backup/restore mas applications

[xuchixc]

• Add new backup and restore actions to existing role db2 to support incremental backup/restore features
• Remove db2_backup and db2_restore roles (replaced by new actions in db2 role
• Add new backup and restore actions to existing role mongodb to support backup/restore features
• Add new roles suite_backup_restore and suite_app_backup_restore to support backup/restore for MAS core and applications
• Add some common tasks and vars to support backup/restore job and storage management, slack notification.
• Add some playbooks for backup/restore MAS Core and applications

All above changes are newly added tasks, will not impact the existing install/uninstall features.