More clean up of orog code

[GeorgeGayno-NOAA]

Continue to remove obsolete code used for the old spectral GFS. This could include:

• Spectral filtering of the terrain.
• Obsolete routines MAKEOA, MAKEOA3, MAKEMT and MAKEPC.

[GeorgeGayno-NOAA]

Numerous updates were added to the branch. So, do some testing to ensure nothing is broken. Testing was performed using e2681c1.

• Branch successfully compiled in 'Debug' mode on Hercules and WCOSS2.
• The grid_gen regression tests were run on all Tier 1 machines (compiled with Intel). All tests passed.
• The grid_gen regression tests were run using Gnu on Hera. All tests completed, but there were slight differences from the baseline (as expected).
• The grid_gen regression tests were run using Intel in 'Debug' mode on Hercules. All tests completed, but there were slight differences from the baseline (as expected).
• On Hercules, the branch was compiled in 'Debug' mode and a C768 uniform grid was created using the script in ./driver_scripts.