Add migration from FFULM to FFMUC #558

Job	Run time
generate_target_matrix	3s
build_firmware (ar71xx-generic)	56m 27s
build_firmware (ar71xx-mikrotik)	50m 59s
build_firmware (ar71xx-nand)	50m 53s
build_firmware (ar71xx-tiny)	35m 13s
build_firmware (ath79-generic)	51m 32s
build_firmware (brcm2708-bcm2708)	49m 25s
build_firmware (brcm2708-bcm2709)	51m 19s
build_firmware (brcm2708-bcm2710)	50m 1s
build_firmware (ipq40xx-generic)	53m 9s
build_firmware (ipq806x-generic)	51m 59s
build_firmware (lantiq-xrx200)	53m 18s
build_firmware (lantiq-xway)	52m 33s
build_firmware (mpc85xx-generic)	51m 14s
build_firmware (mpc85xx-p1020)	52m 47s
build_firmware (mvebu-cortexa9)	51m 40s
build_firmware (ramips-mt7620)	54m 47s
build_firmware (ramips-mt7621)	57m 19s
build_firmware (ramips-mt76x8)	54m 56s
build_firmware (ramips-rt305x)	33m 27s
build_firmware (sunxi-cortexa7)	52m 34s
build_firmware (x86-64)	1h 0m 8s
build_firmware (x86-generic)	57m 43s
build_firmware (x86-geode)	57m 3s
build_firmware (x86-legacy)	55m 37s
create_release	0s
	20h 46m 6s

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