Restructure project layout for better CI/CD integration

- Flattened nested bootupd/bootupd/ structure to root level
- Moved all core project files to root directory
- Added proper Debian packaging structure (debian/ directory)
- Created build scripts and CI configuration
- Improved project organization for CI/CD tools
- All Rust source, tests, and configuration now at root level
- Added GitHub Actions workflow for automated testing
- Maintained all original functionality while improving structure

src/grub2/configs.d/30_uefi-firmware.cfg

@@ -0,0 +1,5 @@
+if [ "$grub_platform" = "efi" ]; then
+        menuentry 'UEFI Firmware Settings' $menuentry_id_option 'uefi-firmware' {
+                fwsetup
+        }
+fi