Create partitioned table p_ci_pipelines and attach first partition

What does this MR do and why?

Create partitioned table p_ci_pipelines and attach first partition

See https://docs.gitlab.com/ee/development/database/partitioning/list.html#step-6---create-parent-table-and-attach-existing-table-as-the-initial-partition

Changelog: added

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Related to #428990 (closed)