Stop building centos 8 stream images

This should be the last piece of cleanup to remove CentOS 8 stream from
Nodepool. We basically tell the builders to forget about these images
which should result in cleanups of all the related records on disk and
in zk.

Change-Id: I71421ce9a10438549ef21441349be84b5d7bd38b

nodepool/nb04.opendev.org.yaml

@@ -132,9 +132,6 @@ diskimages:
 
 ############ CentOS and Fedora (and derivatives) #############
 
-  - name: centos-8-stream
-    elements: []
-
   - name: centos-9-stream
     elements: []
 
@@ -237,17 +234,6 @@ diskimages:
     env-vars:
       DIB_DISTRIBUTION_MIRROR: 'https://mirror.regionone.osuosl.opendev.org/debian'
 
-  - name: centos-8-stream-arm64
-    parent: base
-    pause: true
-    python-path: /usr/bin/python3
-    elements:
-      - centos-minimal
-      - epel
-    release: 8-stream
-    env-vars:
-      DIB_EPEL_DISABLED: '1'
-
   - name: centos-9-stream-arm64
     parent: base
     python-path: /usr/bin/python3

nodepool/nl01.opendev.org.yaml

@@ -176,7 +176,6 @@ providers:
         labels: *provider_pools_labels
 
 diskimages:
-  - name: centos-8-stream
   - name: centos-9-stream
   - name: debian-bookworm
   - name: debian-bullseye

nodepool/nl03.opendev.org.yaml

@@ -408,9 +408,7 @@ providers:
             key-name: infra-root-keys-2024-04-08
 
 diskimages:
-  - name: centos-8-stream
   - name: centos-9-stream
-  - name: centos-8-stream-arm64
   - name: centos-9-stream-arm64
   - name: debian-bookworm
   - name: debian-bookworm-arm64

nodepool/nl04.opendev.org.yaml

@@ -198,7 +198,6 @@ providers:
         labels: *provider_pools_labels
 
 diskimages:
-  - name: centos-8-stream
   - name: centos-9-stream
   - name: debian-bookworm
   - name: debian-bullseye

nodepool/nodepool.yaml

@@ -161,18 +161,6 @@ diskimages:
 
 ############ CentOS and Fedora (and derivatives) #############
 
-  - name: centos-8-stream
-    parent: base
-    pause: true
-    python-path: /usr/bin/python3
-    release: '8-stream'
-    elements:
-      - cache-devstack
-      - centos-minimal
-      - epel
-    env-vars:
-      DIB_EPEL_DISABLED: '1'
-
   - name: centos-9-stream
     parent: base
     pause: false
@@ -398,9 +386,6 @@ diskimages:
   - name: debian-bullseye-arm64
     elements: []
 
-  - name: centos-8-stream-arm64
-    elements: []
-
   - name: centos-9-stream-arm64
     elements: []