Note on obstype terminology for quantity

[hkershaw-brown]

There are places in the code where obstype is used, but the variable/argument is referring to qty

We've updated this in the template model, and when we refactor model_mods, but there is still a lot of 'obstype' hanging around in model_mods and fwd ops. Particularly for people using the QCEFF and debugging their runs, the loose naming type (for qty) adds an unneeded overhead to reading the code.