Fixes #1668. Only allow certain History modes

[mathomp4]

Description

This change makes it so that only instantaneous and time-averaged are allowed as a mode in History collections.

Related Issue

Closes #1668

Motivation and Context

Makes history more precise and protects against possible confusion.

How Has This Been Tested?

Tested with GEOS. If there are no errors, zero-diff. But with errors you get:

pe=00044 FAIL at line=01778    MAPL_HistoryGridComp.F90                 <Invalid mode [time-average] for collection [geosgcm_surf]. Only 'instantaneous' and 'time-averaged' are supported>

or:

pe=00043 FAIL at line=01778    MAPL_HistoryGridComp.F90                 <Invalid mode [instantanious] for collection [geosgcm_prog]. Only 'instantaneous' and 'time-averaged' are supported>

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