Passing custom gunicorn config for flask extension

[M7mdisk]

What needs to get done

Currently, the gunicorn config is hardcoded here. However, in many scenarios, it is essential to override some of the settings (Example: changing worker type to async workers, modifying number of workers, etc).

This can be done either with a file override, passing the GUNICORN_CMD_ARGS env variable, or allowing CLI arguments.

See the docs for more info

In my case, we need to use async workers instead of the default sync ones