Want to add capability for SCAM to be forced by gridded reanalyses/model fields.

### What is the feature/what would you like to discuss?

I'd like to add some new files, modify some existing files in src/physics/cam, src/dynamics/eul, bld/namelist_files ...

### Is there anyone in particular you want to be part of this conversation?

@jtruesdal @adamrher @andrewgettelman @

### Will this change (regression test) answers?

I Don't Know

### Will you be implementing this enhancement yourself?

Yes, but I will need some help