Mova nova configuration initialization

* Move shared volume configuration from stack.sh to stackrc
* Move Nova network and vnc/spice configuration settings from stack.sh
  into lib/nova
* Rename NET_MAN to NETOWRK_MANAGER to match nova.conf attribute name

Change-Id: I9bd2955def553499aa832eda1f0959afe494206a
diff --git a/stackrc b/stackrc
index d418a0e..3da366d 100644
--- a/stackrc
+++ b/stackrc
@@ -196,5 +196,10 @@
 # 5Gb default volume backing file size
 VOLUME_BACKING_FILE_SIZE=${VOLUME_BACKING_FILE_SIZE:-5130M}
 
+# Name of the LVM volume group to use/create for iscsi volumes
+VOLUME_GROUP=${VOLUME_GROUP:-stack-volumes}
+VOLUME_NAME_PREFIX=${VOLUME_NAME_PREFIX:-volume-}
+INSTANCE_NAME_PREFIX=${INSTANCE_NAME_PREFIX:-instance-}
+
 PRIVATE_NETWORK_NAME=${PRIVATE_NETWORK_NAME:-"private"}
 PUBLIC_NETWORK_NAME=${PUBLIC_NETWORK_NAME:-"nova"}