Wicket: migrate from ModalWindow to ModalDialog

For dialogs in the CMS, in the content perspective but also reused in the Experience Manager, brXM 15 uses deprecated org.apache.wicket.extensions.ajax.markup.html.modal.ModalWindow from Wicket 9. This class has been removed from Wicket 10 in favor of org.apache.wicket.extensions.ajax.markup.html.modal.ModalDialog.

However, ModalDialog doesn't have the same functions as ModalDialog, e.g. set initial height, set resizable, how to respond to actions and more. Since the CMS uses these functions, ModalWindow was forked to org.hippoecm.frontend.dialog.wicket9.ModalWindow in module 'community/cms/api' when migrating to Wicket 10 (CMS-15735).

The idea is to pick a simple dialog (e.g. document information dialog) to see what it entails to migrate from ModalWindow to ModalDialog

Ideally the fork would be removed.