Add and backfill project_id for p_ci_runner_machine_builds

What does this MR do and why?

This MR adds and backfills project_id for p_ci_runner_machine_builds as this is a requirement for Cells 1.0. It is based on Max's MR at !164170 (merged).

We have about ~500M records to update which should take 4 weeks to complete on gitlab.com.

Part of #459999 (closed)