Rework the configuration System #61
Description
The current system have many flaws, config reloading doesn't work, it's hard to work with, config upgrading is via manuell strings etc.
We should switch to a proper system, also using a configuration library. I suggest using Configurate with the HOCON format. That allows the users to extract certain values into other files which is especially useful in containerized environment where you want to not mount the config file itself.
It's fine to make a hard cut and don't support config version down to version 1.0 for upgrading.