Investigate (and disable by default) the Sidekiq Memory Killer configs for K8s envs
According to [Sidekiq Memory Killer docs](https://gitlab.com/gitlab-org/gitlab/blob/d4fecb130702b2053d8ed6f78a573caed77759ed/doc/administration/operations/sidekiq_memory_killer.md#L29-44), it'll run as _legacy_ mode by default. Meaning that:
```markdown
In _legacy_ mode, if the Sidekiq process exceeds the allowed RSS then an irreversible
delayed graceful restart will be triggered. The restart of Sidekiq will happen
after `SIDEKIQ_MEMORY_KILLER_GRACE_TIME` seconds.
```
So for K8s envs (Helm charts), ideally we should configure that to be handled per container / pod and disable the lib by default.
issue