Add instance-type to label names

So that it's more clear what kind of instance is used for a given
label, add versions of all the labels of the form $image-$type.

Later, we can remove the $image-$ram versions of the labels.

Change-Id: I8fd30274502a9935755306f2ad5c0c16dde14c41
diff --git a/nodepool/nodepool.yaml b/nodepool/nodepool.yaml
index b45e059..f2e6d29 100644
--- a/nodepool/nodepool.yaml
+++ b/nodepool/nodepool.yaml
@@ -31,6 +31,18 @@
             instance-type: n1-standard-16
             cloud-image: debian-stretch
             volume-size: 40
+          - name: debian-stretch-n1-standard-2
+            instance-type: n1-standard-2
+            cloud-image: debian-stretch
+            volume-size: 40
+          - name: debian-stretch-n1-standard-8
+            instance-type: n1-standard-8
+            cloud-image: debian-stretch
+            volume-size: 40
+          - name: debian-stretch-n1-standard-16
+            instance-type: n1-standard-16
+            cloud-image: debian-stretch
+            volume-size: 40
 labels:
   - name: debian-stretch-8G
     min-ready: 0
@@ -38,3 +50,9 @@
     min-ready: 0
   - name: debian-stretch-60G
     min-ready: 0
+  - name: debian-stretch-n1-standard-2
+    min-ready: 0
+  - name: debian-stretch-n1-standard-8
+    min-ready: 0
+  - name: debian-stretch-n1-standard-16
+    min-ready: 0