Typed methods to get configuration values

[AlexandreGerault]

Hi

I've been struggling sometimes with Laravel and Larastan on high levels. Indeed, the configuration helper config give values as mixed which requires annotation or assertion each time it is used to satisfy static analysis.

I think it can be great to have, like the Request object, typed getters, like ->string($key);, ->integer($key); etc. I made a PR to provide some simple solution that would easily integrate in Laravel codebase (I believe so, correct me if I'm wrong).

This would make it much more easier to satisfy static analysis. Only array might be complaining sometimes.