feat: Wrap viewer app in a docker image

This allows users to instead use a docker image (hosted on the repository), and with a correctly crafted config.yml, do something like

docker run --rm -p 5000:5000 -v $(pwd)/config.yml:/home/root/config.yml localdb-tools

which mounts the local config.yml into the docker image at /home/root/config.yml which is where the app will pick it up from by default.