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

Cargo.toml

@@ -0,0 +1,63 @@
+[package]
+name = "bootupd"
+description = "Bootloader updater"
+license = "Apache-2.0"
+version = "0.2.28"
+authors = ["Colin Walters <walters@verbum.org>"]
+edition = "2021"
+rust-version = "1.84.1"
+homepage = "https://github.com/coreos/bootupd"
+
+include = ["src", "LICENSE", "Makefile", "systemd"]
+
+# See https://github.com/coreos/cargo-vendor-filterer
+[package.metadata.vendor-filter]
+platforms = ["*-unknown-linux-gnu"]
+tier = "2"
+
+[[bin]]
+name = "bootupd"
+path = "src/main.rs"
+
+[dependencies]
+anyhow = "1.0"
+bincode = "1.3.2"
+bootc-internal-blockdev = "0.0.0"
+bootc-internal-utils = "0.0.0"
+cap-std-ext = "4.0.6"
+camino = "1.1.10"
+chrono = { version = "0.4.41", features = ["serde"] }
+clap = { version = "4.5", default-features = false, features = ["cargo", "derive", "std", "help", "usage", "suggestions"] }
+env_logger = "0.11"
+fail = { version = "0.5", features = ["failpoints"] }
+fn-error-context = "0.2.1"
+fs2 = "0.4.3"
+hex = "0.4.3"
+libc = "^0.2"
+libsystemd = ">= 0.3, < 0.8"
+log = "^0.4"
+openat = "0.1.20"
+openat-ext = ">= 0.2.2, < 0.3.0"
+openssl = "^0.10"
+os-release = "0.1.0"
+regex = "1.11.1"
+rustix = { version = "1.0.8", features = ["process", "fs"] }
+serde = { version = "^1.0", features = ["derive"] }
+serde_json = "^1.0"
+tempfile = "^3.20"
+widestring = "1.2.0"
+walkdir = "2.3.2"
+signal-hook-registry = "1.4.5"
+
+[profile.release]
+# We assume we're being delivered via e.g. RPM which supports split debuginfo
+debug = true
+
+[package.metadata.release]
+disable-publish = true
+disable-push = true
+post-release-commit-message = "cargo: development version bump"
+pre-release-commit-message = "cargo: bootupd release {{version}}"
+sign-commit = true
+sign-tag = true
+tag-message = "bootupd {{version}}"