Make STOPPING state optional (#473)

* STOPPING state could be a breaking changee

jobs/cloud_controller_ng/spec

@@ -227,8 +227,9 @@ provides:
   - cc.experimental.use_puma_webserver
   - cc.experimental.use_redis
   - cc.app_log_revision
+  - cc.app_instance_stopping_state
   - cc.deprecated_stacks
-
+  
 consumes:
 - name: database
   type: database
@@ -815,6 +816,9 @@ properties:
   cc.app_log_revision:
     default: false
     description: "Add revision version to an app's log source. Only applies if an App is using revisions. For example, app logs will be prefixed with APP/REV/1/PROC/WEB/0"
+  cc.app_instance_stopping_state:
+    default: true
+    description: "Adds a STOPPING state to app processes to indicate when a process is no longer desired, but has not fully shut down."
   cc.client_max_body_size:
     default: "15M"
     description: "Maximum body size for nginx"