Set docker node version to 14
Node version for Dockerfile-development
and Dockerfile-production
is currently 15. It should be changed to 14.
From Yannis: "Odd versions are considered unstable/cutting edge. Unless there's a specific feature we want, there's no reason to use them. It also gets tricky because the CI image is 14, while the other two are 15. I.e. there could be a bug in ci that is not there for the others."