Move `django_ssl.conf` into `django.conf` (single HTTP/HTTPS server)

[Raruto]

List of changes:

• delete config/_nginx/django_ssl.conf
• update config/nginx/django.conf accordingly in order to use a single HTTP/HTTPS server
• expose WEBGIS_PUBLIC_HOSTNAME environment variable to nginx container (docker-compose.yml)
• expose WEBGIS_PUBLIC_HOSTNAME environment variable to nginx container (docker-compose-consumer.yml)
• update README.md section related to HTTPS additional setup
• refactor run_certbot.sh (to improve readability and terminal output)

Closes: https://github.com/g3w-suite/g3w-suite-docker/issues/67, closes: https://github.com/g3w-suite/g3w-suite-docker/issues/68

[wlorenzetti]

@Raruto I checked every point and tested, if you don't want propose new changes for me it possible merge it on dev.

[Raruto]

The if statement I think is necessary, otherwise we would have a 'loop' of constant redirections. With if we have redirection only on http protocol.

@wlorenzetti given the declarative nature of nginx confing it is not immediately clear whether the ssl options are also sent to the browser when requesting the page as http version:

  ssl_certificate /etc/letsencrypt/live/$WEBGIS_PUBLIC_HOSTNAME/fullchain.pem;
  ssl_certificate_key /etc/letsencrypt/live/$WEBGIS_PUBLIC_HOSTNAME/privkey.pem;

  include /etc/letsencrypt/options-ssl-nginx.conf;
  ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem;

  resolver 8.8.8.8;

  # written like this its doubtful if this condition is executed before or after the previous ssl options
  if ($scheme = http) {
      return 301 https://$server_name$request_uri;
  }

Probably an optimal solution (also in terms of future customizations) could be to keep two separate server sections and share the common portions through the include directive:

server {
    listen 80;
    server_name example.org;

    include mime_types;
    include default_routes;

    location / {
        return 301 https://$host$request_uri;
    }    
}

server {
    listen 443 ssl;
    server_name example.org;

    include mime_types;
    include default_routes;

    include /etc/letsencrypt/options-ssl-nginx.conf;

    ....

    location / {
        proxy_pass http://example.org; #for demo purposes
    }
}

The if statement I think is necessary, otherwise we would have a 'loop' of constant redirections. With if we have redirection only on http protocol.

In https://github.com/g3w-suite/g3w-suite-docker/pull/77#discussion_r979963606 i was thinking if it could be feasible to replace the if condition with the default_server directive (see also: How nginx processes a request), anyway, as you can see I still don't have a very clear idea about it..

BTW, another solution, which would not require changes to the nginx configuration files, could be to always activate ports 80 and 443 inside the container and expose them to the public only when needed (e.g. via docker-compose.override.yml, ref: https://github.com/g3w-suite/g3w-suite-docker/pull/79)

So if there is no rush, I would wait a moment longer before merging this.