Add loggers for generic stages

[mathomp4]

Description

As suggested by @LiamBindle, add loggers to tell when stages are executed during a run.

For now, we use the DEBUG logger as the INFO logger is currently the used by console in GEOSgcm so all prints are in the log if INFO. Eventually, we should update the GEOS logging.yaml file to make, say, a file for MAPL.GENERIC INFO log output.

Related Issue

Motivation and Context

Let's users track down when things run.

How Has This Been Tested?

Model runs. Can't affect the output.

Types of changes

• 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 change)
• Trivial change (affects only documentation or cleanup)

Checklist:

• I have tested this change with a run of GEOSgcm (if non-trivial)
• I have added one of the required labels (0 diff, 0 diff trivial, 0 diff structural, non 0-diff)
• I have updated the CHANGELOG.md accordingly following the style of Keep a Changelog