LuckPerms: Use psql instead of yaml persistence

[vorburger]

Once we bungee jump in multi servers, the LuckPerms persistence needs to be switched from yaml to postgres. Postgres can be set up clsutered and fault redundant. (I want to anyway use Postgres for another project and so could learn one DB for 2, instead of having to figure out MongoDB set up.)

https://github.com/lucko/LuckPerms/wiki/Storage-types