virtualbox: install UnattendedTemplates

Fix automated/unattended guest installs by having the missing templates
where virtualbox expects them.

Fixes #247807.

Changed files
+3
pkgs
applications
virtualization
virtualbox
+3
pkgs/applications/virtualization/virtualbox/default.nix
···
''}
cp -rv out/linux.*/${buildType}/bin/src "$modsrc"
'';
preFixup = optionalString (!headless) ''
···
''}
cp -rv out/linux.*/${buildType}/bin/src "$modsrc"
+
+
mkdir -p "$out/share/virtualbox"
+
cp -rv src/VBox/Main/UnattendedTemplates "$out/share/virtualbox"
'';
preFixup = optionalString (!headless) ''