Fix Docker / npm build about concierge

[doug0102]

@Phanoix I opened a new branch here https://github.com/gctools-outilsgc/concierge/tree/231

I pushed my changes to the dockerfile that worked on Windows as well as updated the readme letting people know about the CRLF issue.

[piet0024]

I was able to build concierge locally on that branch (231). I had to make a change to the Dockerfile here https://github.com/gctools-outilsgc/concierge/blob/231/Dockerfile#L5 I had to change this line to just npm and it built.

[Phanoix]

@piet0024 yeah, looks like the nodejs-npm is now called just npm https://pkgs.alpinelinux.org/package/edge/community/x86_64/npm.