zephyr: shell: add initial SOF custom commands #633

Job	Run time
build-windows (imx8 imx8x imx8m imx8ulp)	8m 35s
build-linux (mnfst, imx8 imx8x imx8m imx8ulp)	5m 40s
build-windows (mtl)	6m 22s
build-linux (mnfst, mtl)	4m 11s
build-windows (tgl tgl-h)	6m 51s
build-linux (mnfst, lnl)	4m 5s
build-windows (-d, mtl)	6m 38s
build-linux (mnfst, tgl tgl-h)	4m 58s
build-linux (zmain, imx8 imx8x imx8m imx8ulp)	5m 31s
LP64-WIP	3m 43s
build-linux (zmain, mtl)	4m 9s
build-linux (zmain, lnl)	4m 2s
manifest-check	52s
build-linux (zmain, tgl tgl-h)	5m 11s
build-linux (-d, mnfst, mtl)	4m 37s
build-linux (mnfst, --all)	9m 52s
compare-linux-win	59s
	1h 26m 16s

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