examples: Add bootc UKI & BLS examples #347

Job	Run time
build (bls, rhel9)	17m 29s
build (bls, arch)	8m 17s
build (bls, fedora)	14m 46s
build (bls, ubuntu)	11m 52s
build (bls, rawhide)	8m 20s
build (uki, arch)	8m 7s
build (unified, fedora)	9m 25s
build (unified-secureboot, fedora)	9m 28s
build (bls, arch, ext4, none)	7m 11s
build (uki, fedora)	9m 32s
build (bls, arch, xfs, none)	9m 1s
	1h 53m 28s

Provide feedback