[Dockerfile] remove unnecessary packages.

[behnejad]

removing unnecessary packages to minimize the docker image.

[jumbi77]

@jc21 This seems right and easy. Any objections to merge this?

[jc21]

There was a reason it was added in the past.. but in general it should be fine, just need to ensure it won't affect node somehow.

[nginxproxymanagerci[bot]]

Docker Image for build 5 is available on DockerHub:

nginxproxymanager/nginx-proxy-manager-dev:pr-4638

[!NOTE] Ensure you backup your NPM instance before testing this image! Especially if there are database changes. This is a different docker image namespace than the official image.

[!WARNING] Changes and additions to DNS Providers require verification by at least 2 members of the community!