Limit CI builds queries to 7 days

This applies to EE queries only. It improves performance of those
queries significantly.

Related to https://gitlab.com/gitlab-org/gitlab-exporter/issues/58
2 jobs for ab-ci-builds-performance in 52 seconds
Status Job ID Name Coverage
  Test
passed #5236784
rspec

00:00:49

passed #5236785
rubocop

00:00:52