Use integer parameters to identify each budget term #95

I think that we should use integer parameters to identify each budget term and bring clarity to this code. Instead of budget_terms( 1, nt) it should be
budget_terms(RUNOFF_WATER, nt) (or whatever it is).

Originally posted by @jedwards4b in #76 (comment)

• @mvertens will resolve in issue Change routing of GLC runoff fluxes to go to ROF instead of OCN #92 PR cism runoff will be now routed to ocn via mosart #94