[cli] add `targetpower` command support (#11321) #260

Job	Run time
expects	31m 58s
packet-verification-1-1-on-1-4	11m 12s
channel-manager-csl	3m 8s
packet-verification-low-power	8m 55s
thread-1-4-gcc-m32	11m 5s
thread-1-4-posix	9m 39s
thread-1-4-gcc-m64	11m 2s
thread-1-4-clang-m32	10m 31s
thread-1-4-clang-m64	9m 59s
upload-coverage	25s
	1h 47m 54s

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