Move ubuntu-bionic/focal nodeset definition

These nodesets are handled by zuul-launcher now, so move them out
of the "nodepool" nodesets file for organizational purposes.

Change-Id: I760690917c4155f89c608b5e8a21ce33213d4204

zuul.d/nodepool-nodesets.yaml

@@ -1,10 +1,4 @@
 # Shared nodesets for all tenants
-- nodeset:
-    name: ubuntu-bionic
-    nodes:
-      - name: ubuntu-bionic
-        label: ubuntu-bionic
-
 - nodeset:
     name: ubuntu-bionic-arm64
     nodes:
@@ -16,9 +10,3 @@
     nodes:
       - name: ubuntu-focal-arm64
         label: ubuntu-focal-arm64
-
-- nodeset:
-    name: ubuntu-focal
-    nodes:
-      - name: ubuntu-focal
-        label: ubuntu-focal

zuul.d/nodesets.yaml

@@ -310,6 +310,20 @@
       name: rockylinux-9
       label: rockylinux-9-16GB
 
+# A legacy nodeset from nodepool
+- nodeset:
+    name: ubuntu-bionic
+    nodes:
+      - name: ubuntu-bionic
+        label: ubuntu-bionic
+
+# A legacy nodeset from nodepool
+- nodeset:
+    name: ubuntu-focal
+    nodes:
+      - name: ubuntu-focal
+        label: ubuntu-focal
+
 - nodeset:
     name: niz-ubuntu-jammy-4GB
     nodes: