feat(chart): Set GOMAXPROCS and GOMEMLIMIT environment variables

[jnoordsij]

Set GOMAXPROCS and GOMEMLIMIT environment variables based on container resources.

The resourceFieldRef is a very specific Kubernetes directive that is created specifically for passing resource-related values, which rounds up the CPU value to the nearest whole number (e.g. 250m to 1) and passes the memory as a numeric value; so 64Mi would result in the environment variable being set to 67108864. This by design makes it completely compatible with Go's API.

An example is documented within Kubernetes documentation itself: https://kubernetes.io/docs/tasks/inject-data-application/environment-variable-expose-pod-information/#use-container-fields-as-values-for-environment-variables.

Inspired by traefik/traefik-helm-chart#1029, this should reduce potential CPU throttling and OOMKills on containers.

This also replaces a reference to .Values.web.containers.env in the metrics-scraper deployment, which I assumed to be an unintented faulty value.

[k8s-ci-robot]

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 37.19%. Comparing base (a49364c) to head (a908b50).
Report is 40 commits behind head on master.

Additional details and impacted files

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