Remove "illuminate/config" dependency

[klimov-paul]

At the present state this package uses Illuminate\Config\Repository for the Artesaos\SEOTools\SEOMeta implementation. This produces an extra dependency to the "illuminate/config" package.

SEOMeta is the only class using Illuminate\Config\Repository - all other SEO tools operate plain arrays.

It is better to refactor Artesaos\SEOTools\SEOMeta removing usage of Illuminate\Config\Repository. It will make this class more consistent, easy for standalone usage and eliminates extra composer dependency.

Q	A
This Package Version	0.15.0
Laravel Framework Version	5.8.31
PHP version	7.2
Operating system	*