Add PlantUML container into ansible

Currently running on hammer with the following command:

docker run -it -d --restart=always -p 8083:8080 malikoth/plantuml-server

this opens plantuml on hammer (public port 8083), there are a few things we should do to make this a bit better:

• Add it to ansible to ensure it's part of our setup
• Stick it behind nginx/haproxy to load balance it
• Make sure it's monitored so we know when it has issues