Add rpm-vendor yum repository

rpmbuilder's vendored third-party RPMs are moving from Gitea's RPM registry
to the artifactapi rpm-vendor local repos. Managed AlmaLinux hosts need the
matching yum repo to install them; this mirrors the existing rpm-internal
repo and selects the per-EL-release repo via os.release.major.

- Add rpm-vendor to profiles::yum::global::repos in
  hieradata/os/AlmaLinux/all_releases.yaml, pointing at
  .../api/v1/local/rpm-vendor-el<major>/ (el8/el9), gpgcheck disabled and
  mirrorlist absent, matching the rpm-internal repo definition.

hieradata/os/AlmaLinux/all_releases.yaml

@@ -85,6 +85,13 @@ profiles::yum::global::repos:
     baseurl: https://artifactapi.k8s.syd1.au.unkin.net/api/v1/local/rpm-internal/
     gpgcheck: false
     mirrorlist: absent
+  rpm-vendor:
+    name: rpm-vendor
+    descr: rpm-vendor repository
+    target: /etc/yum.repos.d/rpm-vendor.repo
+    baseurl: https://artifactapi.k8s.syd1.au.unkin.net/api/v1/local/rpm-vendor-el%{facts.os.release.major}/
+    gpgcheck: false
+    mirrorlist: absent
 
   # Additional repositories - default to absent, roles can override with ensure: present
   # FRRouting repositories