Eliminate some N+1 queries on project-pipeline GraphQL endpoint

What does this MR do?

When fetching stages->jobs data with status details, every job tries to run "retryable?" and it leads to a fetching project, namespace, and route.

This MR adds a "preload" for "project" on jobs.

Related to #323213 (closed)

Screenshots (strongly suggested)

Metrics

This will help us to check later:

75th and 99th percentiles of duration and db count: https://log.gprd.gitlab.net/goto/b08207d25d2259903d5140b938f612e7

Last 7 days:

Does this MR meet the acceptance criteria?

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