[ci] Add package registry promotion pipeline (#198880)

Adds a placeholder pipeline for `kibana / package registry promote`.

Initially, in a follow up PR, this will run a daily promotion of
`docker.elastic.co/package-registry/distribution:lite` to the kibana-ci
namespace. We can also run some verification steps if desired.

The distribution is a relatively large image, and nearly always running
uncached on CI due to the update frequency. This should help us balance
having an up to date image and avoiding cache misses.

.buildkite/pipeline-resource-definitions/kibana-package-registry.yml

@@ -0,0 +1,36 @@
+# yaml-language-server: $schema=https://gist.githubusercontent.com/elasticmachine/988b80dae436cafea07d9a4a460a011d/raw/rre.schema.json
+apiVersion: backstage.io/v1alpha1
+kind: Resource
+metadata:
+  name: bk-kibana-package-registry-promote
+  description: Promote package-registry/distribution:lite
+  links:
+    - url: 'https://buildkite.com/elastic/kibana-package-registry-promote'
+      title: Pipeline link
+spec:
+  type: buildkite-pipeline
+  owner: 'group:kibana-operations'
+  system: buildkite
+  implementation:
+    apiVersion: buildkite.elastic.dev/v1
+    kind: Pipeline
+    metadata:
+      name: kibana / package registry promote
+      description: Promote package-registry/distribution:lite
+    spec:
+      env:
+        SLACK_NOTIFICATIONS_CHANNEL: "#kibana-operations-alerts"
+        ELASTIC_SLACK_NOTIFICATIONS_ENABLED: "false"
+      repository: elastic/kibana
+      branch_configuration: main
+      default_branch: main
+      pipeline_file: ".buildkite/pipelines/fleet/package_registry.yml"
+      provider_settings:
+        trigger_mode: none
+      teams:
+        everyone:
+          access_level: BUILD_AND_READ
+        kibana-operations:
+          access_level: MANAGE_BUILD_AND_READ
+      tags:
+        - kibana

.buildkite/pipeline-resource-definitions/locations.yml

@@ -27,6 +27,7 @@ spec:
     - https://github.com/elastic/kibana/blob/main/.buildkite/pipeline-resource-definitions/kibana-migration-staging.yml
     - https://github.com/elastic/kibana/blob/main/.buildkite/pipeline-resource-definitions/kibana-on-merge-unsupported-ftrs.yml
     - https://github.com/elastic/kibana/blob/main/.buildkite/pipeline-resource-definitions/kibana-on-merge.yml
+    - https://github.com/elastic/kibana/blob/main/.buildkite/pipeline-resource-definitions/kibana-package-registry.yml
     - https://github.com/elastic/kibana/blob/main/.buildkite/pipeline-resource-definitions/kibana-performance-daily.yml
     - https://github.com/elastic/kibana/blob/main/.buildkite/pipeline-resource-definitions/kibana-performance-data-set-extraction-daily.yml
     - https://github.com/elastic/kibana/blob/main/.buildkite/pipeline-resource-definitions/kibana-pointer-compression.yml

.buildkite/pipelines/fleet/package_registry.yml

@@ -0,0 +1,2 @@
+steps:
+  - command: echo "Placeholder"