ci: Add linter stage to workflow #429

Job	Run time
lint	1m 49s
Check DockerHub secrets exist	1s
test (debos-arch)	1m 26s
test (debos-bookworm)	1m 9s
test (debos-bullseye)	57s
test (debos-trixie)	1m 20s
Build Docker container	6m 14s
Run unit tests	2m 59s
recipes on nofakemachine	59s
debian (amd64) on nofakemachine	1m 42s
debian (arm64) on nofakemachine	3m 15s
debian (armhf) on nofakemachine	2m 48s
recipes on qemu	1m 22s
debian (amd64) on qemu	6m 25s
debian (arm64) on qemu	6m 20s
debian (armhf) on qemu	5m 33s
recipes on uml	1m 5s
debian (amd64) on uml	3m 45s
debian (arm64) on uml	3m 32s
debian (armhf) on uml	2m 57s
arch on arch	7m 9s
partitioning on qemu	1m 23s
apertis on uml	3m 45s
partitioning on uml	1m 2s
allgreen	2s
Publish to GHCR	1s
Publish to DockerHub	1s
	1h 9m 1s

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