feat: add GNOME desktop-hypervisor dish for BIOS laptops

- storage/biosboot.ks: GPT disk label with a 2 MiB BIOS boot partition,
  no ESP (pure legacy layout); registered as the 'biosboot' storage choice
- recipe_templates.yaml: make the desktop hypervisor a superset of the
  base hypervisor so GNOME hypervisor dishes get libvirtd + virt-manager
- recipes_manifest.yaml: enable the desktop-hypervisor group targeting
  Fedora 44 (gnome, biosboot, grub, security enabled, gnome initial-setup,
  hardware-support, intelcpu)
- initial-setup/gnome/config.ks: apply the vendor.conf fix (truncate and
  append skip=privacy / providers=local-first!) as an enabled %post
- tests: update BASE_FRAGMENTS fixture to core-explicit.ks (follow-up to
  ccf4f9d)

cook/tests/test_generator.py

@@ -20,7 +20,7 @@ BASE_FRAGMENTS = [
     "core/locale.ks",
     "core/network.ks",
     "core/services.ks",
-    "packages/core.ks",
+    "packages/core-explicit.ks",
     "packages/fedora-remix.ks",
     "packages/hand-picked.ks",
 ]