Add a IncompatibleConfigurationHandlingOption for deleting specific broken keys

[Nytra]

If I have an enum key set in my config. For example: "ENUM_KEY":"Test2" If I later remove the value Test2 from the enum in my code, it makes the mod fail to load because it can't find the value Test2 anymore. This can only be fixed by deleting the entire config or manually removing/fixing that key. Could there be a way for NML to do this automatically? Like for example it could detect the key that threw the error and just remove it. This would be a lot more ideal than nuking the whole config for me.

[XDelta]

Definitely would be nice to have, especially for allowing mods to worry less about breaking changes to configs with updating them to have more or less enums values, or same variable names but new types. Resetting invalid values to whatever default value for that key would be much preferred over the mod failing to load after some update to the mod that changed some configs