Coupler Conventions

all vertical fluxes: upward positive
mask: contains only 0s and 1s; otherwise refer to as area fraction
bang functions!: = first argument is the one being modified.
get_... = no allocations
src/ functions have no dependency on component model data structure (e.g., integrator.u.c.u)
variables in functions - shall we create pointers at the beginning and then be less verbose in the function operations?
decide on what nomenclature and units we want to support for the coupler fields, and list them here
docs: show internal functions?
we shouldn't use magic numbers - e.g. 1309 here

Package import convention

if using a Clima package that we commonly use, use import PackageName as PN (e.g. ClimaAtmos -> CA, SurfaceFluxes -> SF; see package shorthands below)
if using an external package, use import PackageName (e.g. for Dates or JLD2)
if using a module within ClimaCoupler, use import ClimaCoupler: Module1, Module2, ..., and qualify functions/structs within the code using Module1.___, Module2.___, etc
maintain flexibility within this approach, especially to prevent the need to qualify e.g. macros or symbols we use from other packages