🔥 remove user from Dockerfile run stage

[bgauduch]

Despite being a good practice, the non-root user created to run the server in the Dockerfile is creating more harm than good, especially about permission on mounted game files.
See #44 , #49 and #55 for references.

Until finding a proper solution to handle this, we should remove this user for now.

Creating another issue to find away to put it back on: #58