Include confirmDestructive Dialog

[jotoeri]

Just wanted to use the confirmationDialog on Forms and saw i need to take it manually from OC.dialogs. Would imo be nice to have it included in this package!

[susnux]

This will not make it into 4.2.0 but I think about implementing the dialogs based on the new dialog component for 5.0.0, but we could also backport this for 4.3.0 to support this on Nextcloud 27 as well.