Albedos and SW radiation

[patcal]

Problem:
The user needs to be able to pass net downward SW flux and albedo value(s) from CAM to the SIMPLESOM option in DOCN.

Currently the flux values are split into 4 components and passes via cam_out. CIME calculates the albedo values and passes the net shortwave flux to DOCN ( x2o%rAttr(kswnet,n) ). For simple model configurations, we need to add the flexibility for the user to optionally pass their own albedo values and bypass the computations. The simplest usage scenario is the user specifies the net downward SW flux at the surface and then for a given albedo provided in a namelist the net SW that the DOCN receives is just the product:
CAM{ provide Fsw } --> CIME{ SWnet = My_Albedo*Fsw } --> DOCN{ use SWnet }

(From there, more general options all the way up to the current implementation can be added)