Extend CLI gunicorn settings (memory options)

There are some issues related to memory consumption in Climate DT. This can be reduced by using some additional options of gunicorn that modify the workers' behavior like max_requests. For that, we can include more worker options inside the API CLI. To add:

• threads
• worker_connections
• max_requests
• max_requests_jitter
• timeout
• graceful_timeout
• keepalive

https://docs.gunicorn.org/en/22.0.0/settings.html