[Docker] Fix NGINX_PORT port configuration

[allyoucanmap]

Some functionality are not working if we change the NGINX_PORT env.

Steps:

• change the NGINX_PORT to 4000 and start the application
• add a zip shapefile to the static/data folder
• open the viewer at http://localhost:4000
• select the zip shapefile layer as input
• click on create a tileset

Expected:

The tileset creation process starts

Current:

There is a connection error

[allyoucanmap]

Solved by 51e4e76