Add nested-virt-centos-8-stream label

Change [1] added nested virtualization labels for Ubuntu Bionic and
CentOS 7, and change [2] for CentOS 8. This patch extends that to CentOS
8 Stream.

[1] https://review.opendev.org/#/c/683431/
[2] https://review.opendev.org/#/c/738161/

Change-Id: Ie8b532184d0cddad63e876a30ef521103dc11b84

nodepool/nl02.openstack.org.yaml

@@ -49,6 +49,8 @@ labels:
     min-ready: 0
   - name: nested-virt-centos-8
     min-ready: 0
+  - name: nested-virt-centos-8-stream
+    min-ready: 0
 
 providers:
   - name: limestone-regionone
@@ -178,6 +180,11 @@ providers:
             flavor-name: 'nodepool.0'
             diskimage: centos-8
             key-name: infra-root-keys-2020-05-13
+          - name: nested-virt-centos-8-stream
+            min-ram: 8000
+            flavor-name: 'nodepool.0'
+            diskimage: centos-8-stream
+            key-name: infra-root-keys-2020-05-13
 
   - name: airship-kna1
     region-name: 'Kna1'

nodepool/nl03.openstack.org.yaml

@@ -63,6 +63,8 @@ labels:
     min-ready: 0
   - name: nested-virt-centos-8
     min-ready: 0
+  - name: nested-virt-centos-8-stream
+    min-ready: 0
 
 providers:
   - name: inap-mtl01
@@ -417,6 +419,13 @@ providers:
             volume-size: 80
             diskimage: centos-8
             key-name: infra-root-keys-2020-05-13
+          - name: nested-virt-centos-8-stream
+            min-ram: 8000
+            flavor-name: v2-highcpu-8
+            boot-from-volume: true
+            volume-size: 80
+            diskimage: centos-8-stream
+            key-name: infra-root-keys-2020-05-13
 
   - name: linaro-us
     region-name: 'RegionOne'

nodepool/nl04.openstack.org.yaml

@@ -34,6 +34,8 @@ labels:
     min-ready: 0
   - name: nested-virt-centos-8
     min-ready: 0
+  - name: nested-virt-centos-8-stream
+    min-ready: 0
 
 providers:
   - name: ovh-bhs1
@@ -158,6 +160,11 @@ providers:
             flavor-name: ssd-osFoundation-3
             diskimage: centos-8
             key-name: infra-root-keys-2020-05-13
+          - name: nested-virt-centos-8-stream
+            min-ram: 8000
+            flavor-name: ssd-osFoundation-3
+            diskimage: centos-8-stream
+            key-name: infra-root-keys-2020-05-13
 
   - name: ovh-gra1
     region-name: 'GRA1'