[develop] Rename variables that store task names

[gsketefian]

DESCRIPTION OF CHANGES:

To be consistent with the naming convention used for variables that specify per-task properties (e.g. PPN_RUN_FCST, WTIME_RUN_FCST, MAXTRIES_RUN_FCST), rename variables that store the task names (e.g. RUN_FCST_TN) so that the "TN" part is at the beginning, e.g. TN_RUN_FCST.

This PR is part of a series to enhance the verification capabilities of the SRW App.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

TESTS CONDUCTED:

• hera.intel
• orion.intel
• cheyenne.intel
• cheyenne.gnu
• gaea.intel
• jet.intel
• wcoss2.intel
• NOAA Cloud (indicate which platform)
• Jenkins
• fundamental test suite
• comprehensive tests (specify which if a subset was used)

The following fundamental tests were run on Hera using the Intel compiler. All were successful.

From fundamental.hera.gnu.com and/or fundamental.hera.intel.nco:

• MET_ensemble_verification
• MET_verification
• MET_verification_only_vx
• community_ensemble_2mems
• community_ensemble_2mems_stoch
• grid_RRFS_CONUS_25km_ics_FV3GFS_lbcs_FV3GFS_suite_GFS_2017_gfdlmp
• grid_RRFS_CONUS_25km_ics_FV3GFS_lbcs_FV3GFS_suite_GFS_2017_gfdlmp_regional_plot
• grid_RRFS_CONUS_25km_ics_FV3GFS_lbcs_FV3GFS_suite_GFS_v15p2
• grid_RRFS_CONUS_25km_ics_FV3GFS_lbcs_FV3GFS_suite_GFS_v16
• grid_RRFS_CONUS_25km_ics_FV3GFS_lbcs_RAP_suite_HRRR
• grid_RRFS_CONUS_25km_ics_GSMGFS_lbcs_GSMGFS_suite_GFS_v15p2
• grid_RRFS_CONUScompact_25km_ics_HRRR_lbcs_HRRR_suite_HRRR
• grid_RRFS_CONUScompact_25km_ics_HRRR_lbcs_HRRR_suite_RRFS_v1beta
• pregen_grid_orog_sfc_climo

From previous versions of fundamental.hera.gnu.com and/or fundamental.hera.intel.nco:

• grid_RRFS_CONUScompact_25km_ics_HRRR_lbcs_RAP_suite_HRRR
• grid_RRFS_CONUScompact_25km_ics_HRRR_lbcs_RAP_suite_RRFS_v1beta
• nco_grid_RRFS_CONUScompact_25km_ics_HRRR_lbcs_RAP_suite_HRRR

DOCUMENTATION:

The documentation has been updated to reflect the changes in the PR.

ISSUE:

Resolves issue #599.

CHECKLIST

• My code follows the style guidelines in the Contributor's Guide
• I have performed a self-review of my own code using the Code Reviewer's Guide
• I have commented my code, particularly in hard-to-understand areas
  N/A
• My changes need updates to the documentation. I have made corresponding changes to the documentation
• My changes do not require updates to the documentation (explain).
• My changes generate no new warnings
• New and existing tests pass with my changes
• Any dependent changes have been merged and published
  N/A

[MichaelLueken]

@gsketefian These changes look good to me!

[MichaelLueken]

@gsketefian The issues from Jenkins are due to the fact that I had to manually abort the Hera tests (even though the Hera tests are shut off in the Jenkinsfile). All tests have successfully passed the Jenkins tests, so I will now move forward with merging this PR.