RFE: Make Nginx Access Log Configurable via Environment Variable

[popecruzdt]

Nginx Access Logs are configured in nginx.conf. By default, in the configuration used by the Docker images available on Dockerhub have Nginx Access Logs disabled.

https://github.com/Dynatrace/easyTravel-Docker/blob/master/images/nginx/conf/nginx.conf

For those that wish to use the images on Dockerhub (not build their own) and have Nginx Access Logs enabled, it would be helpful if this configuration was controlled through an Environment Variable. Similar to those configurations already referencing an Environment Variable in the nginx.conf file.

upstream easytravelfrontend {
        server $ET_FRONTEND_LOCATION;
    }