Give Essentials the ability to auto-update the config.yml

Feature description

See Above
How the feature is useful

Essentials has one of the longest configs out there. Not having to through the whole config every time there is an update would be helpful.

this could be helpful on the occasion that they add a new line to the config instead of regenerating and resetting it

This won't be happening anytime soon, because auto-updating causes all comments to get nuked.

On the bright side, config changes per version are usually not too big, and the defaults are usually designed in a way such that it doesn't mess with your existing stuff. It's up to you if you want to re-generate it, and stay up to date on the newest features. I recommend using a diff checking tool which should easily point out differences between old config and the new.

Reopening as a 3.0 goal. Also this is something I may want a stab at

The philosophy throughout the lifetime of 2.x has always been that when the plugin is updated, it should maintain the previous behaviour until the server owner decides to manually upgrade their config. For 3.x I'm considering a move to Configurate (possibly YAML but I'd like to switch to HOCON), and automatic migrations could be considered then.