add clelery flower docker service

[jokiefer]

Environment

• Python version:
• MrMap version:

User Story

As a Administrator, I want manage and control celery workers, so that can watch the concrete worker status and task processing.

Acceptance criteria

• Given I am a Administrator, when I open https://localhost/celery-flower, I want to see the flower administration page.

Additional Information

The official flower docker container