Cgroups: enable feature flag by default

What

Change the value of run_cmds_in_cgroups on by default

Why

We've been running cgroups in GitLab.com since October 2022 and we haven't seen any fundamental problems with it. We've also extended cgroups to include cpu_quota_us.

In https://gitlab.com/gitlab-com/gl-infra/reliability/-/issues/23573 we are noticing that some git commands aren't getting assigned to the repository cgroup because sometimes feature flags aren't set and since this is by default false we go to the runsv cgroup.

Reference: https://gitlab.com/gitlab-com/gl-infra/reliability/-/issues/23573#note_1379307222 Reference: #4102 (closed)