Fix #795, Remove legacy time header format support

[skliper]

Describe the contribution
Fix #795
Fix #92
Collapses options down to just 32 bit second, 16 bit subsecond, always big endian. Removes old defines, and errors out if the configuration is set to a format that was removed.

Testing performed
Built and make test with SIMULATION=native ENABLE_UNIT_TESTS=true, passes test.

Expected behavior changes
Time in header always big endian.

System(s) tested on

• Hardware: cFS Dev VM
• OS: Ubuntu 18.04
• Versions: main bundle plus Fix #711, Separate secondary header access functions #726, with this commit on top (c039fb4 is the commit for this PR, or those marked with Fix Collapse down to 1 time format for packet headers (missions can customize msg module for alternates) #795)

Additional context
#726

Third party code
None

Contributor Info - All information REQUIRED for consideration of pull request
Jacob Hageman - NASA/GSFC

[astrogeco]

CCB 2020-08-19 APPROVED, provide example for override. See idea in #726

[skliper]

Rebased on integration-candidate