Merge branch 'mahf708/eamxx/ne4mvk' (PR #7789)

Introducing RCS (and removing MVK) to ATM.

Highlights:

perturb test mod for creating necessary perturbation
RCS system test with rcs_perts (manipulate perturbation) and est_stats for statistical testing
rcs_stats can be triggered from the command line too (some details in rcs_stats were generated by bot)
note a limitation in cice (in eam and cice buildnml, ntasks are wrong in multi-deriver multi-instance setup #7788)
automatically generated docs

cocreated with bots

[BFB]

Author: bartgol

cime_config/tests.py

@@ -798,6 +798,8 @@
         "inherit" : (
         ),
         "tests" : (
+            "RCS_P8_C4.ne30pg2_ne30pg2.F2010-SCREAMv1.eamxx-perturb",  # 8 nodes, about 1.9 hours on pm-gpu
+            "RCS_P1_C4.ne4pg2_ne4pg2.F2010-SCREAMv1.eamxx-perturb",    # 1 node, about 22min on pm-gpu
             "ERP_D_Lh182.ne4pg2_ne4pg2.F2010-SCREAMv1",
             "ERS_Ln362.ne30pg2_ne30pg2.F2010-SCREAMv1"
             )