WIP: GitLab CI/CD pipelines storage improvement

Description

This merge request adds an architectural blueprint describing the work that needs to be done to regain control over ci_builds table, reduce the size of this table, and help with PostgreSQL scaling problems.

Review app: https://blueprint-gb-pipelines-storage-improvements.about.gitlab-review.app/handbook/engineering/architecture/blueprints/pipelines/storage/index.html

.gitlab/issue_templates/blog-PYB-post.md

@@ -10,7 +10,7 @@
 ### Checklist
-- [ ] If [time sensitive](https://about.gitlab.com/handbook/marketing/blog/#time-sensitive-posts-official-announcements-company-updates-breaking-changes-and-news)
+- [ ] If [time sensitive](https://about.gitlab.com/handbook/marketing/blog/#process-for-time-sensitive-posts)
   - [ ] Added desired publish date as due date
   - [ ] Added ~"priority" label