Merge branch 'fix-multiline-env-substitution' into 'master'

| `HELM_PROD_VALUES`       | The [Values file](https://helm.sh/docs/chart_template_guide/values_files/) to use with the production environment | _none_ |

| `HELM_PROD_ENVIRONMENT_URL` | The production environment url **including scheme** (ex: `https://my-application.public.k8s.domain.com`) Do not use variable inside variable definition as it will result in a two level cascade variable and gitlab does not allow that. | _none_ |

#### Dynamic Values

#### Dynamic Values and Variables

You have to be aware that your deployment (and cleanup) scripts have to be able to cope with various environments

(`review`, `integration`, `staging` and `production`), each with different application names, exposed routes, settings, ...

Part of this complexity can be handled by the lookup policies described above (ex: one resource per env).

In order to be able to implement some **genericity** in your scripts and templates, you should use generic [values](https://helm.sh/docs/chart_best_practices/values/)

dynamically set and passed by the template:

In order to be able to implement some **genericity** in your scripts and templates:

1. you should use generic [values](https://helm.sh/docs/chart_best_practices/values/) dynamically set and passed by the template:

* `env`: the environment type (`review`, `integration`, `staging` or `production`)

* `hostname`: the environment hostname, extracted from `${CI_ENVIRONMENT_URL}` (got from [`environment:url`](https://docs.gitlab.com/ee/ci/yaml/#environmenturl) - see `OS_REVIEW_ENVIRONMENT_SCHEME`, `OS_REVIEW_ENVIRONMENT_DOMAIN`, `OS_STAGING_ENVIRONMENT_URL` and `OS_PROD_ENVIRONMENT_URL`)

2.  you should use available environment variables:

  * any [GitLab CI variable](https://docs.gitlab.com/ee/ci/variables/#predefined-environment-variables)

    (ex: `${CI_ENVIRONMENT_URL}` to retrieve the actual environment exposed route)

  * any [custom variable](https://docs.gitlab.com/ee/ci/variables/#custom-environment-variables)

    (ex: `${SECRET_TOKEN}` that you have set in your project CI/CD variables)

> :warning: 

>

> In order to be properly replaced, variables in your YAML value file shall be written with curly braces (ex: `${MYVAR}` and not `$MYVAR`).

>

> Multiline variables must be surrounded by double quotes and you might have to disable line-length rule of yamllint as they are rewritten on a single line.

> 

> ```yaml

>  tlsKey: "${MYKEY}"  # yamllint disable-line rule:line-length

> ```

### `helm-lint` job

This job [examines your chart for possible issues](https://helm.sh/docs/helm/helm_lint/) and uses the following variables:

  }

  function awkenvsubst() {

    awk '{while(match($0,"[$]{[^}]*}")) {var=substr($0,RSTART+2,RLENGTH -3);gsub("[$]{"var"}",ENVIRON[var])}}1'

    awk '{while(match($0,"[$]{[^}]*}")) {var=substr($0,RSTART+2,RLENGTH -3);val=ENVIRON[var];gsub(/["\\]/,"\\\\&", val);gsub("\n", "\\n", val);gsub("\r", "\\r", val);gsub("[$]{"var"}",val)}}1'

  }

  # deploy application