add documentation related to apidoc job

# 🗒 ApiDoc

## Description

Creates a versioned HTML documentation from API annotations in your source

code using [apiDoc](https://www.apidocjs.com/).

## How to use it

1. Prepare your project with API annotations in your source code following

   [apiDoc format](https://apidocjs.com/#examples) and your [apiDoc

   configuration file](https://apidocjs.com/#configuration).

2. Choose a version in [version list](#versions)

3. Add the corresponding URL to your `.gitlab-ci.yml` file (see [Getting

   started](/getting-started)). Example:

    ```yaml

    include:

      - remote: 'https://jobs.go2scale.io/apidoc.yml'

    ```

4. If you need to customize the job (stage, variables, ...) 👉 check the [jobs

   customization](/getting-started/#jobs-customization)

5. Well done, your job is ready to work ! 😀

## Job details

* Job name: `documentation`

* Docker image:

[`node`](https://hub.docker.com/r/_/node)

* Default stage: `build`

* When: `always`

### Variables

| Name | Description | Default |

| ---- | ----------- | ------- |

| `APIDOC_CONFIG_PATH` | Path to config file or to directory containing config file (apidoc.json or apidoc.config.js) | `.` |

| `APIDOC_OUTPUT_PATH` | Output directory path | `/apidoc_build` |

| `APIDOC_TEMPLATE_PATH` | Path to template folder | `/usr/lib/node_modules/apidoc/template/` |

| `DOCUMENTATION_DISABLE` | Disable build | |

### Artifacts

Result of documentation build is [exposed

as](https://docs.gitlab.com/ee/ci/yaml/#artifactsexpose_as) `Documentation` in

merge requests.

## Versions

* **Latest** (current -> `2020-08-07_1`) : `https://jobs.go2scale.io/latest/apidoc.yml`

* **Tag `2020-08-07_1`** : `https://jobs.go2scale.io/2020-08-07_1/apidoc.yml`

    * Initial version

    entrypoint: [""]

  stage: build

  variables:

    - APIDOC_CONFIG: ''

    - APIDOC_OUTPUT_PATH: './public'

    - APIDOC_CONFIG_PATH: '.'

    - APIDOC_OUTPUT_PATH: './apidoc_build'

    - APIDOC_TEMPLATE_PATH: '/usr/lib/node_modules/apidoc/template/'

  script:

    - npm install apidoc -g

    - apidoc --verbose -c $APIDOC_CONFIG -o $APIDOC_OUTPUT_PATH

    - npm install apidoc@0.24.0 -g

    - apidoc --verbose -c "$APIDOC_CONFIG_PATH" -o "$APIDOC_OUTPUT_PATH" -t "$APIDOC_TEMPLATE_PATH"

  artifacts:

    when: always

    expose_as: "Documentation"

    paths:

      - public/

      - "$APIDOC_OUTPUT_PATH"

      #  - public/

  rules:

    - if: '$DOCUMENTATION_DISABLE'

      when: never