Add a tool to run multiple YAML cases locally (NOAA-EMC#3004)

This adds the script `generate_workflows.py`, which provides a flexible,
multipurpose feature set to run suites of cases from YAMLs with minimal
intervention. For most cases, this will allow users to easily run CI
tests on a local platform, including updating the user's crontab
automatically.

Resolves NOAA-EMC#2989

.github/CODEOWNERS

@@ -208,3 +208,6 @@ ush/python/pygfs/ufswm/gfs.py @aerorahul
 ush/python/pygfs/ufswm/ufs.py @aerorahul
 ush/python/pygfs/utils/__init__.py @aerorahul
 ush/python/pygfs/utils/marine_da_utils.py @guillaumevernieres @AndrewEichmann-NOAA
+
+# Specific workflow scripts
+workflow/generate_workflows.sh @DavidHuber-NOAA