Add server sekelton

This adds the first server skeleton. For testing you have to set up a local mysql database (mariadb) and add a config.json file for your local user/password/database name as described in the readme. This code doesn't yet use the database but the code that connects to it (and checks for errors) is already in: when we can't connect to the specified database we fail with a fatal error. Otherwise i stripped everything we don't need for now (authentication and endpoints are coming later). Just comment on any code lines you have issues with/can't figure out what they are there for.

When everything is set up, this an be tested by accessing http://localhost:8080 (browser/curl) after running the server.