Add RUN_POSTPROCESSING variable to env_run.xml

This variable will be FALSE by default, but setting it to TRUE will
(eventually) run some postprocessing scripts as part of the default workflow.
In that respect, its behavior will be similar to how DOUT_S controls the
short-term archiver.

cime_config/config_component.xml

@@ -568,6 +568,16 @@
     If TRUE, short term archiving will be turned on.</desc>
   </entry>
 
+  <entry id="RUN_POSTPROCESSING">
+    <type>logical</type>
+    <valid_values>TRUE,FALSE</valid_values>
+    <default_value>FALSE</default_value>
+    <group>run_data_archive</group>
+    <file>env_run.xml</file>
+    <desc>Logical to run post-processing analysis tools.
+    If TRUE, post-processing scripts will be run</desc>
+  </entry>
+
   <entry id="SYSLOG_N">
     <type>integer</type>
     <default_value>900</default_value>