Adds default setting & settings filters

[ouun]

In many scenarios it is very helpful to filter the predefined & defined settings. E.g. if you have custom Cookie names you need to predefine for users. Or you run a network that has speecific default settings based.

[coreykn]

Thanks for opening this, @ouun. I definitely see how that would be helpful. Would something like pre_option_{$option} and/or option_{$option} work better instead though?

[ouun]

Absolutely! That makes totally sense, simply did not think around the corner. 🙄 Thanks a lot for working on this.