Feature Request: Allow global overrides

[Adam Brown]

Rather than manually specifying overrides, it would be nice to be able to just set a "fallback" boolean in the setting config file.

If a setting('value') isn't set, and the fallback boolean is set to true, then the package would check for config('value') and return that value if it is set. If config('value') isn't set, then it would return null.

[Denis Dulici]

It depends. I may not want to override some/most of config and in such a case must manually specify the overrides to skip.