* add Placeholder and make default buttons flags consistent w old behaviour
* DialogWindow ops
* make QuickDialog use DialogWindow
* Update Content.Client/UserInterface/Controls/DialogWindow.xaml
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Co-authored-by: deltanedas <@deltanedas:kde.org>
Co-authored-by: metalgearsloth <31366439+metalgearsloth@users.noreply.github.com>
(cherry picked from commit 6b03aaaec78bd50c8f4730c9aa7d0f5cea76e782)
