save land diagnostics in output dir

[juliasloan25]

as we do for atmos and coupler diagnostics

More generally, we should unify the approaches we use for atmos, land, and coupler diagnostics. Right now they're all set up in different places, and there is some confusing overlap (easy to have duplicate diagnostics) with atmos diagnostics being specified in both atmos and coupler. We need to think about the structure of where we save outputs, and unify how we specify which diagnostics we want from each component.

currently:

• coupler diagnostics (F_turb_energy) saved in output/~run_name~/output_active/
• atmos diagnostics saved in output/~run_name~/output_active/clima_atmos/
• land diagnostics saved in output/~run_name~/artifacts/

we want:

• coupler diagnostics saved in output/~run_name~/output_active/coupler/
• atmos diagnostics saved in output/~run_name~/output_active/clima_atmos/
• land diagnostics saved in output/~run_name~/output_active/clima_land/