recipe-generator: Update to new template structure with install and live templates

- Replaced individual templates with unified 'install' (desktop, server, hypervisor) and 'live' (live-desktop, live-server) templates

- Added new modifiers: variant_type, hypervisor-type, desktop, initial-setup, virtualization

- Updated generate_recipe.py to handle new modifier structure with additive flags

- Updated recipes_manifest.yaml with new modifier structure

- Added missing fragment files and directories

fragments/platform/generic-rawhide/bootloader/grub.ks

@@ -1,3 +0,0 @@
-# GRUB bootloader configuration for live media (no location, minimal timeout)
-
-bootsupport --timeout=1 # Set the GNU GRUB bootloader timeout to 1 and to location to none

fragments/platform/generic-rawhide/bootloader/systemd-boot.ks

@@ -1,3 +0,0 @@
-# systemd-boot bootloader configuration for live media (no location, minimal timeout)
-
-bootsupport --sdboot --location=none --timeout=1 # Use systemd-boot and set location to none