Crop calendar inputs needed with CRU-JRA climate

[samsrabin]

(Step 2 in parent issue #3319.)

• Crop maturity requirements (GDDs): stream_fldFileName_cultivar_gdds
• "Baseline" GDD20: stream_fldFileName_gdd20_baseline

GDD-generating workflow here, although see potential changes to that workflow discussed in #3319. Use results from #3320, but make sure to "tweak" lat/lons to ensure b4b across processor counts.

Also update the namelist defaults to point to the new files, at least if using a CRU-JRA compset.

[samsrabin]

Blocked by #3451 because we wanted these updated datasets to come in on the alpha 5.4 branch.