metadata.json: Add EL 9 (CentOS, Alma, Rocky, Oracle) support

This also adjusts hiera.yaml to reduce the amount of data that need to
be duplicated. This hiera.yaml is now effectively the same as the
hiera.yaml used by default with PDK: https://github.com/puppetlabs/pdk-templates/blob/main/moduleroot_init/hiera.yaml.erb

hiera.yaml

@@ -5,6 +5,10 @@ defaults:
   data_hash: 'yaml_data'
 hierarchy:
   - name: 'Distribution name and major version'
-    path: "os/%{facts.os.name}.%{facts.os.release.major}.yaml"
+    paths:
+      - "os/%{facts.os.name}.%{facts.os.release.major}.yaml"
+      - "os/%{facts.os.family}.%{facts.os.release.major}.yaml"
   - name: 'Distribution family'
-    path: "os/%{facts.os.family}.yaml"
+    paths:
+      - "os/%{facts.os.name}.yaml"
+      - "os/%{facts.os.family}.yaml"

metadata.json

@@ -13,6 +13,18 @@
   ],
   "issues_url": "https://github.com/voxpupuli/puppet-puppetboard/issues",
   "operatingsystem_support": [
+    {
+      "operatingsystem": "AlmaLinux",
+      "operatingsystemrelease": [
+        "9"
+      ]
+    },
+    {
+      "operatingsystem": "CentOS",
+      "operatingsystemrelease": [
+        "9"
+      ]
+    },
     {
       "operatingsystem": "Debian",
       "operatingsystemrelease": [
@@ -27,6 +39,18 @@
         "13"
       ]
     },
+    {
+      "operatingsystem": "OracleLinux",
+      "operatingsystemrelease": [
+        "9"
+      ]
+    },
+    {
+      "operatingsystem": "Rocky",
+      "operatingsystemrelease": [
+        "9"
+      ]
+    },
     {
       "operatingsystem": "Ubuntu",
       "operatingsystemrelease": [