Order of operations in update aux

[kmdeck]

Describe the bug

The land model creates anupdate_aux! function which calls update_aux! of the component models in turn. This should be independent of the order of the component models.

Currently, if we switch canopy to update before soil, we get errors in canopy radiation because of soil albedo, which is updated in soil's update aux. Since canopy radiation depends on soil albedo, it should be in update_boundary_fluxes instead.

More broadly, we should rename these functions so that they clarify their role: update_independent_cache and update_dependent_cache? Should we remove the name aux entirely?

Come back to this when we have sussed out what these roles are ^^
@juliasloan25

To Reproduce

Check out PR#907