[Helm] Set QoS policies for CP and PL

[karimatwa]

Motivation:

• Set load generators as burstable by default. This allows resources to scale dynamically based on load tests. Throttling or evicting these jobs when fully saturated makes sense, as the load test can simply be restarted if necessary.
• Set control plane to guaranteed QoS class by default, as its role as the orchestrator of load generators makes evictions unacceptable.
  https://kubernetes.io/docs/concepts/workloads/pods/pod-qos/#quality-of-service-classes

Modifications:

• Set same control plane resource requests and resource limits in order to ensure guaranteed QoS class.
• Set different load generator resource requests and resource limits in order to ensure burstable QoS class.