New Dockerfile

[tjstavenger-pnnl]

• Add Dockerfile to run datavoyager (would be nice to get this built and deployed to https://hub.docker.com/)
• Configured server to listen on 0.0.0.0 to open server up for Docker -- this has an artifact of opening other deployements up to all IPs, too
• Added yarn start:headless option to remove the --open parameter as it isn't needed in Docker
• Updated README.md with Docker build & run instructions

While running Travis CI build on my fork to verify my changes didn't break anything tested, I found the build has an out of memory error. I increased the --max-old-space-size to work around the issue.

[tjstavenger-pnnl]

I brought in the same changes from PR #839 to updated node-sass. That lets it build with Node 14.4.0. I also changed the .travis-ci.yml and Dockerfile to use 14.4.0

I didn't change any of the other dependencies -- quite a few are out of date. I took a couple of hours yesterday to try to just update all to the latest and quickly found there are code and dependency incompatibilities. I made it through a few of them, but decided to stop when I got pretty deep into the code. I figure it would be better left to a person more familiar with the code base.