upstream CI: Enable CentOS 8 Stream for PR and nightly tests.

Add configuration to build a testing CentOS 8 stream image and to
execute upstream tests using that image in pull requests (Ansible
2.9) and on the nightly tests (all supported Ansible versions).

tests/azure/nightly.yml

@@ -52,7 +52,7 @@ stages:
       scenario: fedora-latest
       ansible_version: ""
 
-# CentoOS 9
+# CentoOS 9 Stream
 
 - stage: CentOS9_Ansible_2_9
   dependsOn: []
@@ -81,6 +81,44 @@ stages:
       scenario: centos-9
       ansible_version: ""
 
+# CentOS 8 Stream
+
+- stage: c8s_Ansible_2_9
+  dependsOn: []
+  jobs:
+  - template: templates/group_tests.yml
+    parameters:
+      build_number: $(Build.BuildNumber)
+      scenario: c8s
+      ansible_version: ">=2.9,<2.10"
+
+- stage: c8s_Ansible_Core_2_11
+  dependsOn: []
+  jobs:
+  - template: templates/group_tests.yml
+    parameters:
+      build_number: $(Build.BuildNumber)
+      scenario: centos-8
+      ansible_version: "-core >=2.11,<2.12"
+
+- stage: c8s_Ansible_Core_2_12
+  dependsOn: []
+  jobs:
+  - template: templates/group_tests.yml
+    parameters:
+      build_number: $(Build.BuildNumber)
+      scenario: c8s
+      ansible_version: "-core >=2.12,<2.13"
+
+- stage: c8s_Ansible_latest
+  dependsOn: []
+  jobs:
+  - template: templates/group_tests.yml
+    parameters:
+      build_number: $(Build.BuildNumber)
+      scenario: c8s
+      ansible_version: ""
+
 # CentOS 8
 
 - stage: CentOS8_Ansible_2_9