Merge branch 'builds-api-nplusone' into 'master'

Resolve "N+1 queries with /projects/:project_id/builds API endpoint"

Closes #41957

See merge request gitlab-org/gitlab-ce!16445

(cherry picked from commit 191b5153)

7e084984 Add n plus one spec for v3 builds api
c9a1a155 Fix N+1 in v3 builds API
c9840842 Eager load user, runner, pipeline and its creator
09118796 Add N+1 query spec for Jobs API
87cc0373 Fix N+1 builds query in Jobs list API
a4d7f155 Extend N+1 Builds and Jobs API specs
8cef1f4c Add missing newline in Jobs API spec
feb34497 Use preload instead of includes to avoid joins