Converting ACME from cime2 to ESMCI cime

This is on the general ESMCI wiki so everyone can review and spot potential problems.

Guide for converting ACME from cime2 to the latest ESMCI cime

Prior to doing the upgrade, work with ESMCI/cime standalone.

1. Do one last merge from ACME/cime to ESMCI/cime

2. Freeze development in ESMCI/cime as much as possible (will still need pe-layout updates for ongoing v1 work).

3. Verify that cime_config/acme/machines/config_machines.xml works for all ACME platforms using CIME-only cases and tests.

Doing the upgrade

After updating ACME master and creating/checking out a branch for the work:

1. Replace the existing subtree with the latest ESMCI CIME

2. Verify CIME-only cases still work (this is extra-careful)

3. Try a simple land-only I-case. (the case that uses the least number of active components)