Make server configs used across saves by default

[pupnewfster]

Make server configs generate in the normal config folder and allow overriding them on a per-world basis by use of the previously default location serverconfigs. This includes a minor breaking change in FML, but from a modpack/user perspective all existing worlds should continue to function identically as it will just load the configs they already have in serverconfigs as if they were overrides.

Requires neoforged/FancyModLoader#48

Edit: Just as a note this doesn't change anything behavior wise about defaultconfigs. Those still will function exactly as they currently do.

[HeatherComputer]

Huge fan of this - most people do not care for world-specific configs and leaving it as an option is great for the few that do

...and having stuff back in the config folder helps a lot of external systems which can't override configs in a world that does not yet exist

[quat1024]

Sounds great. I know i've decided against using server configs in the past just cause i knew i'd get a hundred "help i can't find the config" questions