Extract should redirect logic to method on base middleware

[standaniels]

In some cases the hideDefaultLocaleInURL isn't a static value and reading the config wouldn't suffice. For example:

• Domain example.nl
  • Has locales:
    • nl
  • Default locale: nl
  • Hide default locale: true
• Domain example.be
  • Has locales:
    • fr
    • nl
  • Default locale: fr
  • Hide default locale: false

This PR extracts the logic to determine whether the request should be redirected to the (non-) localized URL or not to a method on the base middleware class, so a user could write their own middleware, but are able to extend the package middleware; they only need to overwrite the shouldRedirectToLocalizedUrl and shouldRedirectToNonLocalizedUrl methods.

What do you think?