[develop] Consolidate verification tasks using retrieve_data.py (#864)

As described in Issue #850, the scripts for retrieving observation data for verification are quite convoluted and hard-to-maintain due to the constant changing of naming conventions on HPSS. We can leverage the functionality of the retrieve_data.py script to greatly simplify and consolidate this code, and that's what this PR achieves.

In addition, many other bug fixes and improvements are included:
* The j-Jobs and exscripts for the retrieving of CCPA, MRMS, NDAS, and NOHRSC data are consolidated into a single set of scripts.
* Verification tests that use staged data on disk no longer need to manually deactivate "get_obs" tasks; now tasks check if staged data was specified and ensure it is all present
* Obs locations (CCPA_OBS_DIR, MRMS_OBS_DIR, NDAS_OBS_DIR, and NOHRSC_OBS_DIR) no longer need a specific directory structure, though the file format remains the same
* Major improvements to mrms_pull_topofhour.py; now has a main() function for importing, uses proper command-line arguments with argparse, uses f-strings to simplify print statements, and raises an exception if no observation file is found instead of failing silently
* Fixes bug in retrieve_data.py where filenames in tarballs containing full paths are not properly extracted
* Removes "choices" for --data_type argument in retrieve_data.py: the data type is customizable via the config file (which is also customizable), so we shouldn't hard-code arbitrary choices. Missing data types are gracefully handled later anyway.
* Add all verification tests to a coverage suite
* Add new test custom_ESGgrid_Great_Lakes_snow_8km that specifies a custom domain for a snowstorm in February 2023, re-using data that was staged for the AQM test. This is part of an effort to expand testing that will be completed in a subsequent PR, including explicit tests for winter precipitation verification.
* Add cold-air-damming test to all comprehensive test lists, not just orion.
* Test MET_ensemble_verification_only_vx_time_lag now works on most platforms, not just hard-coded to Hera
* Comments related to verification obs in config_defaults.yaml are consolidated and relevant information moved to new consolidated obs-pulling script

jobs/JREGIONAL_GET_OBS_NDAS → jobs/JREGIONAL_GET_VERIF_OBS

@@ -1,9 +1,9 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 #
 #-----------------------------------------------------------------------
 #
-# This script pulls NDAS observation data for comparison to the model.
+# This script checks, pulls, and stages observation data for model verification.
 #
 #-----------------------------------------------------------------------
 #
@@ -51,8 +51,8 @@ print_info_msg "
 Entering script:  \"${scrfunc_fn}\"
 In directory:     \"${scrfunc_dir}\"
 
-This is the J-job script for the task that pulls NDAS observation data
-for verification purposes.
+This is the J-job script for the task that checks, pulls, and stages
+observation data for verification purposes.
 ========================================================================"
 
 #
@@ -64,7 +64,7 @@ for verification purposes.
 #
 #-----------------------------------------------------------------------
 #
-$SCRIPTSdir/exregional_get_obs_ndas.sh || \
+$SCRIPTSdir/exregional_get_verif_obs.sh || \
 print_err_msg_exit "\
 Call to ex-script corresponding to J-job \"${scrfunc_fn}\" failed."
 #