Revise ncclimo default invocation

zppy chooses to invoke ncclimo in MPI mode with requesting 4 nodes for climo jobs. Based on email exchanges with @czender: For all low resolution simulations, use the default background mode instead, will potentially reduce queue time and save resources. MPI mode can be useful for HR simulations, and those can either be assigned multiple nodes in MPI mode or accomplished in background mode by ratcheting down the number of concurrent processes (to relieve RAM pressure) with the --job_nbr option.

Start by locating zppy's ncclimo invocation and the climo job logic that selects MPI mode and requests four nodes. Check how low-resolution and HR simulations are identified, then verify that low-resolution jobs use background mode while HR jobs retain an appropriate MPI or reduced-concurrency path; done means the generated invocations match those rules.

Written by the indexing model from the issue text.