feat: restructure onhost folders and naming #847

Job	Run time
cargo fmt	15s
codespell	12s
⚖️ Check third party licenses	6m 14s
ubuntu / stable / coverage	3m 48s
cargo shear (unused dependencies)	22s
Build release binaries	2m 7s
Unit test for embedded downloader	29s
Unit, docs and onhost integration tests	2m 22s
tests as root	3m 41s
K8s integration tests (part2)	9m 39s
cargo doc	1m 38s
cargo clippy	2m 13s
K8s integration tests (flux-self-update)	6m 2s
K8s integration tests (part1)	5m 12s
build-widows-binary	8m 6s
security / Rust audit scanner	2m 33s
k8s-e2e-tests / K8s e2e tests infra	7m 12s
k8s-e2e-tests / K8s e2e tests	4s
🟢 All required checks and tests pass	4s
	1h 2m 13s

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