libvirt: move xml files to an xml subdirectory

The libvirt/ directory is a bit cluttered.  Move xml files to a
subdirectory.

Test plan:
PASS: Regression for default and mad examples
PASS: unit test of the affected replacement values for all
      configurations

Story: 2010816
Task: 48613

Change-Id: I7a8552616cce9ac4639d3c2c67d5a019f7f06bdc
Signed-off-by: Michel Thebeau <michel.thebeau@windriver.com>

libvirt/functions.sh

@@ -167,10 +167,10 @@ create_controller() {
 
         if ([ "$CONFIGURATION" == "simplex" ] || [ "$CONFIGURATION" == "duplex" ]); then
             DISK_0_SIZE=600
-            cp controller_allinone.xml ${DOMAIN_FILE}
+            cp xml/controller_allinone.xml ${DOMAIN_FILE}
         else
             DISK_0_SIZE=250
-            cp controller.xml ${DOMAIN_FILE}
+            cp xml/controller.xml ${DOMAIN_FILE}
         fi
         sed -i -e "
             s,%NAME%,${CONTROLLER_NODE},
@@ -265,7 +265,7 @@ create_node() {
 
     sudo qemu-img create -f qcow2 ${DISK_LOCATION}/${NODE}-0.img 200G
     sudo qemu-img create -f qcow2 ${DISK_LOCATION}/${NODE}-1.img 200G
-    cp ${IDENTITY}.xml ${DOMAIN_FILE}
+    cp xml/${IDENTITY}.xml ${DOMAIN_FILE}
     sed -i -e "
         s,%NAME%,${NODE},
         s,%CPU%,${CPU},