Split msg coverage tests into multiple executables to be able to cover all implementations

[skliper]

Is your feature request related to a problem? Please describe.
Currently with just one executable it's not possible to cover all implementations with one build/run, so source selection is used:

cFE/modules/msg/ut-coverage/CMakeLists.txt

Lines 28 to 45 in 5e41330

	# Add extended header tests if appropriate
	if (MISSION_INCLUDE_CCSDSEXT_HEADER)
	list(APPEND ut_${DEP}_tests
	test_msg_ext_not.c
	test_cfe_msg_ccsdsext.c)
	else (MISSION_INCLUDE_CCSDSEXT_HEADER)
	list(APPEND ut_${DEP}_tests
	test_msg_prionly.c)
	endif (MISSION_INCLUDE_CCSDSEXT_HEADER)
	# Add the correct message id test
	if (MISSION_MSGID_V2)
	list(APPEND ut_${DEP}_tests
	test_cfe_msg_msgid_v2.c)
	else (MISSION_MSGID_V2)
	list(APPEND ut_${DEP}_tests
	test_cfe_msg_msgid_v1.c)
	endif (MISSION_MSGID_V2)

Describe the solution you'd like
Split into smaller units, probably makes sense to do the 1 for 1 pattern like OSAL and then all the implementations can be covered from one build/run.

Describe alternatives you've considered
None

Additional context
Related to #631, and the suggested responses.

Requester Info
Jacob Hageman - NASA/GSFC