Implement extra env pattern

Closes #1399 (closed)

Testing

First, grab the test.values.yaml file below:

test.values.yaml

gitlab:
  migrations:
    extraEnv:
      extraEnv: migrations-env-test
  gitaly:
    extraEnv:
      extraEnv: gitaly-env-test
  sidekiq:
    extraEnv:
      extraEnv: sidekiq-env-test
  mailroom:
    enabled: true
    extraEnv:
      extraEnv: mailroom-env-test
  gitlab-shell:
    extraEnv:
      extraEnv: gitlab-shell-env-test
  geo-logcursor:
    enabled: true
    extraEnv:
      extraEnv: geo-logcursor-env-test
  gitlab-exporter:
    extraEnv:
      extraEnv: gitlab-exporter-env-test
  webservice:
    extraEnv:
      extraEnv: webservice-env-test
  task-runner:
    extraEnv:
      extraEnv: task-runner-env-test

global:
  # uncomment me to test the global setting for extraEnv
  #   extraEnv:
  #     extraEnv: all-powerful-global
  appConfig:
    incomingEmail:
      enabled: true
      password:
        secret: somesecret
  geo:
    enabled: true
    role: secondary
    psql:
      host: some-host-for-geo
      password:
        secret: some-secret-for-geo
  psql:
    host: some-host-for-geo
    password:
      secret: some-secret-for-geo

certmanager-issuer:
  email: mnielsen@gitlab.com

Then, run:

helm template -n test gitlab . -f examples/kind/values-ssl.yaml | less

You can search through for <chart>-env-test to see where all the extraEnvs are. You can also un-comment the global.extraEnv section and re-run helm template to confirm that it overrides all the extraEnvs across the charts.