Feat/add empty responses

[kevinccbsg]

What kind of change does this PR introduce? (check at least one)

• Bugfix
• Feature
• Test

Description:

This PR allows the option to provide an empty response in the OpenAPI Docs. This is possible using the OpenAPI yml.

In order to do this, we have to use this comment.

/**
 * GET /api/v1
 * @summary This is the summary of the endpoint
 * @return 200 - success response - application/json
 * @return 400 - Bad request response
 */

This closes #165

[bri06]

LGTM