Add unittests for dss_host.py and dss_target.py #69

Job	Run time
lint (pycodestyle) / build-aws	5m 9s
lint (shellcheck) / build-aws	4m 37s
build (dss-sdk-build) / build-aws	9m 43s
build (dss-sdk-unit-test) / build-aws	8m 11s
scan / build-aws	9m 10s
	36m 50s

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