test(manager): add installation test for Rocky9 distribution

Added:
- configuration file for Rocky9 distro;
- jenkinsfile to run Manager installation test on Rocky9

ref:
scylladb/scylla-manager#3854

configurations/manager/rocky8.yaml

@@ -1,3 +1,3 @@
 ami_id_monitor: 'ami-011ef2017d41cb239'  # Rocky Linux 8 (Official) image, region - us-east-1
 ami_monitor_user: 'rocky'
-monitor_branch: 'branch-4.7'  # Pass it as debian image is not the formal monitor image
+monitor_branch: 'branch-4.7'  # Pass it as rocky image is not the formal monitor image

configurations/manager/rocky9.yaml

@@ -0,0 +1,3 @@
+ami_id_monitor: 'ami-09fb459fad4613d55'  # Rocky Linux 9 (Official) image, region - us-east-1
+ami_monitor_user: 'rocky'
+monitor_branch: 'branch-4.7'  # Pass it as rocky image is not the formal monitor image

jenkins-pipelines/manager/rocky9-manager-install.jenkinsfile

@@ -0,0 +1,15 @@
+#!groovy
+
+// trick from https://github.com/jenkinsci/workflow-cps-global-lib-plugin/pull/43
+def lib = library identifier: 'sct@snapshot', retriever: legacySCM(scm)
+
+managerPipeline(
+    backend: 'aws',
+    region: 'us-east-1',
+    test_name: 'mgmt_cli_test.MgmtCliTest.test_manager_installed_and_functional',
+    test_config: '''["test-cases/manager/manager-installation-set-distro.yaml", "configurations/manager/rocky9.yaml"]''',
+
+    post_behavior_db_nodes: 'destroy',
+    post_behavior_loader_nodes: 'destroy',
+    post_behavior_monitor_nodes: 'destroy',
+)