Add concept of state overlays #2024

Job	Run time
Build (C9S)	1m 30s
build-integration	4m 7s
Code style	50s
Build (Fedora)	1m 20s
Build - FCOS minimal	1m 46s
Debian Stable with sign-ed25519 and FUSE 2	7m 50s
Debian Stable with curl, sign-ed25519, no gpgme, FUSE 3	6m 53s
Debian Stable 32 bit	7m 54s
Debian Stable without libsystemd	7m 38s
Debian Testing	8m 1s
Debian Testing with libsoup3	7m 5s
Debian stable + static-prepareroot	7m 17s
Ubuntu Latest Release	7m 52s
Privileged testing	46s
	1h 10m 49s

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