[PROD-16118] Adding feature to control user/group

Change allows to set user and group for QEMU processes run by the system instance
And specify whether libvirt should dynamically change file ownership to match the
Configured user/group above
Related-Prod: PROD-16118

Change-Id: I700f7cd373fffea82a0b1c3b0e22bfd9b2ef3a48
diff --git a/README.rst b/README.rst
index c3a67f1..64d546a 100644
--- a/README.rst
+++ b/README.rst
@@ -280,6 +280,19 @@
           max_processes: 4096
         host: node-12.domain.tld
 
+Group and user to be used for QEMU processes run by the system instance
+
+.. code-block:: yaml
+
+    nova:
+      compute:
+        enabled: true
+        ...
+        qemu:
+          user: nova
+          group: cinder
+          dynamic_ownership: 1
+
 Group membership for user nova (upgrade related)
 
 .. code-block:: yaml