Possible enhancements to the Docker setup

[niconoe]

• Check if it's necessary to build our own Nginx image or if we could rather configure a standard one
• Check if including nginx is the best approach for production
• Tweak gunicorn (multiple workers>)
• Write shell script to make the release process easier
• Consider using GH actions to build and push the docker images when a new tag is created?
• Run Django in production (update in local_settings_docker.template.py)
• Automatically create a superuser?
• Building the GBIF alert takes some time, see if we can make it more efficient (multi-stage? better grouping of RUN?)
• Also run cronjobs (import observations + send notification emails) from Docker, so users don't need to run those manually
• Make the Docker-compose setup also suitable for development