Introduce Heads' SBOM (OSFF grant)

WiP, will edit before doing PRs State of the Art (prior work done elsewhere that is significative) - nix buildstack - https://arnout.engelen.eu/blog/nix-state-of-the-sbom/ - sbomnix - nix-sbom-helper - coreboot - Dasharo/coreboot: extending SBOM https://github.com/Dasharo/coreboot/pull/859 - linux - Linux kernel SBOM : https://lwn.net/Articles/1055009/ - Heads modules/* SBOM implementation: - Mbed-TLS example: https://github.com/Mbed-TLS/mbedtls/pull/9777 ---- Grant Grant https://opensourcefirmware.foundation/funding/