DELETE /articles/{slug}

[nomisRev]

In order to fully support articles we need to implement a DELETE article for slug,
according to following OpenAPI Spec.

    delete:
      tags:
        - Articles
      summary: Delete an article
      description: Delete an article. Auth is required
      operationId: DeleteArticle
      parameters:
        - name: slug
          in: path
          description: Slug of the article to delete
          required: true
          schema:
            type: string
      responses:
        '200':
          $ref: '#/components/responses/EmptyOkResponse'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '422':
          $ref: '#/components/responses/GenericError'
      security:
        - Token: []

1. Implement deleteArticleForSlug in ArticlePersistence and add the corresponding SQL to SqlDelight if it doesn't exist.
2. Create articles.kt in routes if does not exist, implement the DELETE route using ArticlePersistence
3. Add test that verifies the behavior works

Please assign yourself to this ticket before starting, and if you run into any issues please raise a PR so I can provide help and support directly in the code.

Thank you in advance for your interest in the project! Happy hacktoberfest!