MAPG-203 add Dockerfile for multiplayer (NodeJS)

docker/Dockerfile-multi

@@ -0,0 +1,16 @@
+FROM ubuntu:focal
+
+ENV DEBIAN_FRONTEND noninteractive
+
+# Install necessary packages
+RUN apt update --fix-missing
+RUN apt install -y curl build-essential
+
+# Install Node.js and required packages
+RUN curl -sL https://deb.nodesource.com/setup_14.x | bash -
+RUN apt install -y nodejs
+
+VOLUME /var/www/mapguesser
+WORKDIR /var/www/mapguesser
+
+ENTRYPOINT /usr/bin/node --inspect=0.0.0.0:9229 multi