[Ops/BK] Migrate serverless-release (elastic#179063)

Candidate for the first buildkite pipeline to be migrated from
`kibana-buildkite` to the elastic-wide system.
The pipeline represented is:
https://buildkite.com/elastic/kibana-serverless-release-1

Quirk:
- When the pipeline was created, another pipeline was created (that's
since now been removed) with the same name, so this was assigned a `-1`
at the end. Hopefully not a problem when we're considering the takeover

This PR contains:
- `kibana-serverless-release.yml` - an automatic rewrite of the pipeline
resource from
https://github.com/elastic/kibana-buildkite/blob/main/pipelines/kibana-serverless-release.tf
- `locations.yml` - since we collect the pipelines in such a file to
avoid bloating `catalog-info.yaml`, the location needs to be updated
- `create_deployment_tag.yml` - updates the pipeline implementations
with agent targeting rules (since we no longer can use
(https://github.com/elastic/buildkite-agent-manager)

---------

Co-authored-by: Jon <jon@budzenski.me>

.buildkite/pipeline-resource-definitions/kibana-serverless-release.yml

@@ -0,0 +1,42 @@
+# yaml-language-server: $schema=https://gist.githubusercontent.com/elasticmachine/988b80dae436cafea07d9a4a460a011d/raw/rre.schema.json
+apiVersion: backstage.io/v1alpha1
+kind: Resource
+metadata:
+  name: buildkite-pipeline-serverless-release
+  description: Initiate kibana serverless releases
+  links:
+    - title: Pipeline
+      url: https://buildkite.com/elastic/kibana-serverless-release-1
+spec:
+  type: buildkite-pipeline
+  owner: 'group:kibana-operations'
+  system: buildkite
+  implementation:
+    apiVersion: buildkite.elastic.dev/v1
+    kind: Pipeline
+    metadata:
+      name: kibana / serverless / release
+      description: Initiate kibana serverless releases
+    spec:
+      env:
+        SLACK_NOTIFICATIONS_CHANNEL: '#kibana-operations-alerts'
+        ELASTIC_SLACK_NOTIFICATIONS_ENABLED: 'false'
+      default_branch: main
+      repository: elastic/kibana
+      pipeline_file: .buildkite/pipelines/serverless_deployment/create_deployment_tag.yml
+      provider_settings:
+        build_branches: false
+        build_pull_requests: false
+        publish_commit_status: false
+        trigger_mode: none
+        build_tags: false
+      teams:
+        kibana-release-operators:
+          access_level: MANAGE_BUILD_AND_READ
+      schedules:
+        Weekly automated promotion to QA:
+          cronline: 0 6 * * 1
+          message: Weekly automated promotion to QA
+          env:
+            AUTO_SELECT_COMMIT: 'true'
+          branch: main

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

@@ -7,3 +7,4 @@ spec:
   type: url
   targets:
     - 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-serverless-release.yml

.buildkite/pipelines/serverless_deployment/create_deployment_tag.yml

@@ -1,7 +1,10 @@
 ## Creates deploy@<timestamp> tag on Kibana
 
 agents:
- queue: kibana-default
+  image: family/kibana-ubuntu-2004
+  imageProject: elastic-images-qa
+  provider: gcp
+  machineType: n2-standard-2
 
 steps:
   - label: "List potential commits"